diff --git a/Documentation/ProjectFile/properties/property/BishopsPowerLaw/t_exponent.md b/Documentation/ProjectFile/properties/property/BishopsPowerLaw/t_exponent.md
index 6f6002095400ad77e24cbb92d1472d038b8d747f..2d394068c663637602107f1a8624da1cd7eacc5a 100644
--- a/Documentation/ProjectFile/properties/property/BishopsPowerLaw/t_exponent.md
+++ b/Documentation/ProjectFile/properties/property/BishopsPowerLaw/t_exponent.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::BishopsPowerLaw::_m
+\copydoc MaterialPropertyLib::BishopsPowerLaw::m_
diff --git a/Documentation/ProjectFile/properties/property/BishopsSaturationCutoff/t_cutoff_value.md b/Documentation/ProjectFile/properties/property/BishopsSaturationCutoff/t_cutoff_value.md
index d4b89ee3b3f46469e736f2e4007ece743220b47a..d421451c439c927d20fecbc70a4127fa23e3c823 100644
--- a/Documentation/ProjectFile/properties/property/BishopsSaturationCutoff/t_cutoff_value.md
+++ b/Documentation/ProjectFile/properties/property/BishopsSaturationCutoff/t_cutoff_value.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::BishopsSaturationCutoff::_S_L_max
+\copydoc MaterialPropertyLib::BishopsSaturationCutoff::S_L_max_
diff --git a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_exponent.md b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_exponent.md
index 6a8d8e0cf000a5bac7d83bb6a7f827e390707518..8ceb19fd37ed47f2b144ad96e8096ddaebf0a1a1 100644
--- a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_exponent.md
+++ b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_exponent.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::_m
+\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::m_
diff --git a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_maximum_capillary_pressure.md b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_maximum_capillary_pressure.md
index 107022f8bee4b8ccf41cb3997d612b7bbd37c574..dfd97571274e34b9f859ba95dd9c3685b73b2dfd 100644
--- a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_maximum_capillary_pressure.md
+++ b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_maximum_capillary_pressure.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::_p_cap_max
+\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::p_cap_max_
diff --git a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_p_b.md b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_p_b.md
index 3250b1e35587503f3bf8ffa6bb706d9be8908b90..01450c7ff34453aeb272adeb130256cb442f95f1 100644
--- a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_p_b.md
+++ b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_p_b.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::_p_b
+\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::p_b_
diff --git a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_residual_liquid_saturation.md b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_residual_liquid_saturation.md
index 82a7afe7442aa3b3df1522929c9ee637a58b80b7..5a5d803f5566308ebd6310a451ecc0a2935538f5 100644
--- a/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_residual_liquid_saturation.md
+++ b/Documentation/ProjectFile/properties/property/CapillaryPressureVanGenuchten/t_residual_liquid_saturation.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::_S_L_res
+\copydoc MaterialPropertyLib::CapillaryPressureVanGenuchten::S_L_res_
diff --git a/Documentation/ProjectFile/properties/property/Curve/t_independent_variable.md b/Documentation/ProjectFile/properties/property/Curve/t_independent_variable.md
index 480403e37992ccb94c5a70740527ef7b48ccd23b..ef5673605ed3db3d95e96c0606bc660b09721856 100644
--- a/Documentation/ProjectFile/properties/property/Curve/t_independent_variable.md
+++ b/Documentation/ProjectFile/properties/property/Curve/t_independent_variable.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::CurveProperty::_independent_variable
+\copydoc MaterialPropertyLib::CurveProperty::independent_variable_
diff --git a/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_exponents.md b/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_exponents.md
index af8a83d9d2fecfdbf9652df9f836f9e876a03d9c..21ca23c367baf4022fa50a99e0ee08076dffedfb 100644
--- a/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_exponents.md
+++ b/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_exponents.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::PermeabilityOrthotropicPowerLaw::_lambda
+\copydoc MaterialPropertyLib::PermeabilityOrthotropicPowerLaw::lambda_
diff --git a/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_intrinsic_permeabilities.md b/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_intrinsic_permeabilities.md
index ca5090d0f2ad6129b74de4f5b373c7e025bb80bd..06c4279713909361ce7c19b77a87aab7226a5ada 100644
--- a/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_intrinsic_permeabilities.md
+++ b/Documentation/ProjectFile/properties/property/PermeabilityOrthotropicPowerLaw/t_intrinsic_permeabilities.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::PermeabilityOrthotropicPowerLaw::_k
+\copydoc MaterialPropertyLib::PermeabilityOrthotropicPowerLaw::k_
diff --git a/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_initial_porosity.md b/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_initial_porosity.md
index c074a144af6ee3c49809ac8ba0214a7d733ec4ef..9772612485313d86dce98b43232ea2315dd3f00a 100644
--- a/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_initial_porosity.md
+++ b/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_initial_porosity.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::PorosityFromMassBalance::_phi0
+\copydoc MaterialPropertyLib::PorosityFromMassBalance::phi0_
diff --git a/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_maximal_porosity.md b/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_maximal_porosity.md
index f6543731b8947c9591c90fe505b4466445c56097..363a3ef28d8ceee4a2f1ce09c32a84e7fc489f39 100644
--- a/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_maximal_porosity.md
+++ b/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_maximal_porosity.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::PorosityFromMassBalance::_phi_max
+\copydoc MaterialPropertyLib::PorosityFromMassBalance::phi_max_
diff --git a/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_minimal_porosity.md b/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_minimal_porosity.md
index 03eb4483676972e2c6edcb225a8d68ebdda198ba..3adad567c8b9c2278ce54941873973fa01f3bbb9 100644
--- a/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_minimal_porosity.md
+++ b/Documentation/ProjectFile/properties/property/PorosityFromMassBalance/t_minimal_porosity.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::PorosityFromMassBalance::_phi_min
+\copydoc MaterialPropertyLib::PorosityFromMassBalance::phi_min_
diff --git a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_exponents.md b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_exponents.md
index e6e47b53960568f852d3d743d69b377a36264caf..e4da0268415d78a7934dbcf649a2e29f69e2f919 100644
--- a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_exponents.md
+++ b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_exponents.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::SaturationDependentSwelling::_lambda
+\copydoc MaterialPropertyLib::SaturationDependentSwelling::lambda_
diff --git a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_lower_saturation_limit.md b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_lower_saturation_limit.md
index ee7249121aabac9dd8293735dcb3b5c4c0faea90..67f7b7f1c88215212698e94e8c9532f91a16fcf6 100644
--- a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_lower_saturation_limit.md
+++ b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_lower_saturation_limit.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::SaturationDependentSwelling::_S_min
+\copydoc MaterialPropertyLib::SaturationDependentSwelling::S_min_
diff --git a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_swelling_pressures.md b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_swelling_pressures.md
index d64f031defe699bcc9780c70c609fbf74748bca3..1874ce5087a68c3a77c5d1975e86d531582a14e1 100644
--- a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_swelling_pressures.md
+++ b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_swelling_pressures.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::SaturationDependentSwelling::_p
+\copydoc MaterialPropertyLib::SaturationDependentSwelling::p_
diff --git a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_upper_saturation_limit.md b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_upper_saturation_limit.md
index 79f2466dd7cd82e704366722e56bb51b31e155d0..aea11dc9d167dca6341bf34f7a39dc232da765cf 100644
--- a/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_upper_saturation_limit.md
+++ b/Documentation/ProjectFile/properties/property/SaturationDependentSwelling/t_upper_saturation_limit.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::SaturationDependentSwelling::_S_max
+\copydoc MaterialPropertyLib::SaturationDependentSwelling::S_max_
diff --git a/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_initial_porosity.md b/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_initial_porosity.md
index 0f27976edd401cb600c90ef2bbacf1125e06b3d5..5290a21e6bd620a4a7549aab72a921dc54af8383 100644
--- a/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_initial_porosity.md
+++ b/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_initial_porosity.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::TransportPorosityFromMassBalance::_phi0
+\copydoc MaterialPropertyLib::TransportPorosityFromMassBalance::phi0_
diff --git a/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_maximal_porosity.md b/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_maximal_porosity.md
index 6b1397084cd99498d3883efa4cf7cdf7f7a5de64..4e58e374dbd134e6a04d169d0936af76fd07d64b 100644
--- a/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_maximal_porosity.md
+++ b/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_maximal_porosity.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::TransportPorosityFromMassBalance::_phi_max
+\copydoc MaterialPropertyLib::TransportPorosityFromMassBalance::phi_max_
diff --git a/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_minimal_porosity.md b/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_minimal_porosity.md
index 28b256970038b36a79a3e428e5c6978ba9f3b596..c40c34e962a6a63f699c5bf21566b69466e9c21f 100644
--- a/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_minimal_porosity.md
+++ b/Documentation/ProjectFile/properties/property/TransportPorosityFromMassBalance/t_minimal_porosity.md
@@ -1 +1 @@
-\copydoc MaterialPropertyLib::TransportPorosityFromMassBalance::_phi_min
+\copydoc MaterialPropertyLib::TransportPorosityFromMassBalance::phi_min_
diff --git a/MaterialLib/MPL/Component.cpp b/MaterialLib/MPL/Component.cpp
index ad24c9e12bc0bea80fd436529f6b7d75541ba803..6393d4a009ef8802ff2514bac0d9fe017f38ee27 100644
--- a/MaterialLib/MPL/Component.cpp
+++ b/MaterialLib/MPL/Component.cpp
@@ -26,17 +26,17 @@ Component::Component(std::string const& component_name,
 {
     if (properties)
     {
-        overwriteExistingProperties(_properties, *properties, this);
+        overwriteExistingProperties(properties_, *properties, this);
     }
 }
 
 Property const& Component::property(PropertyType const& p) const
 {
-    return *_properties[p];
+    return *properties_[p];
 }
 
 bool Component::hasProperty(PropertyType const& p) const
 {
-    return _properties[p] != nullptr;
+    return properties_[p] != nullptr;
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Component.h b/MaterialLib/MPL/Component.h
index 733ef53201380192ded090e260e59bdc4eedf1e0..3e9774089a8ba744e9654641b6146c61295d22fa 100644
--- a/MaterialLib/MPL/Component.h
+++ b/MaterialLib/MPL/Component.h
@@ -71,7 +71,7 @@ public:
 
 protected:
     /// The property array of the component.
-    PropertyArray _properties;
+    PropertyArray properties_;
 };
 
 /// Method for creating a new component based on the specified component name.
diff --git a/MaterialLib/MPL/CreatePhase.h b/MaterialLib/MPL/CreatePhase.h
index 3db6b8cb354ae2ab433ed0148ba031ab5e655811..83acf94527c750f69597d841b690ecfa18a4af8c 100644
--- a/MaterialLib/MPL/CreatePhase.h
+++ b/MaterialLib/MPL/CreatePhase.h
@@ -36,7 +36,7 @@ class PiecewiseLinearInterpolation;
 namespace MaterialPropertyLib
 {
 /// A method that parses the phase details and stores them in the private
-/// _phases member.
+/// phases_ member.
 ///
 /// This method creates the phases of the medium. Unlike a medium, a phase may
 /// have a name. However, this is silly at the moment since this name still has
diff --git a/MaterialLib/MPL/MaterialSpatialDistributionMap.cpp b/MaterialLib/MPL/MaterialSpatialDistributionMap.cpp
index 7f122ceb1babdc3e4785edfa9fb61857cbf1e4b6..0fbe5e4f941e7b32bf7a36d0182a653c0f04c1fd 100644
--- a/MaterialLib/MPL/MaterialSpatialDistributionMap.cpp
+++ b/MaterialLib/MPL/MaterialSpatialDistributionMap.cpp
@@ -25,17 +25,17 @@ Medium const* MaterialSpatialDistributionMap::getMedium(
     std::size_t const element_id) const
 {
     auto const material_id =
-        _material_ids == nullptr ? 0 : (*_material_ids)[element_id];
+        material_ids_ == nullptr ? 0 : (*material_ids_)[element_id];
 
-    return _media.at(material_id).get();
+    return media_.at(material_id).get();
 }
 
 
 void MaterialSpatialDistributionMap::checkElementHasMedium(std::size_t const element_id)
 {
     auto const material_id =
-            _material_ids == nullptr ? 0 : (*_material_ids)[element_id];
-    if (_media.find(material_id) == _media.end())
+        material_ids_ == nullptr ? 0 : (*material_ids_)[element_id];
+    if (media_.find(material_id) == media_.end())
     {
         OGS_FATAL(
             "There is no medium definition for element {:d} with material "
diff --git a/MaterialLib/MPL/MaterialSpatialDistributionMap.h b/MaterialLib/MPL/MaterialSpatialDistributionMap.h
index 4a82dfcf68c7dffd41c33dd250e86e8a59d8faa0..7ee0bd04af092a5e294c0664719397cb22809167 100644
--- a/MaterialLib/MPL/MaterialSpatialDistributionMap.h
+++ b/MaterialLib/MPL/MaterialSpatialDistributionMap.h
@@ -31,7 +31,7 @@ public:
     MaterialSpatialDistributionMap(
         std::map<int, std::shared_ptr<Medium>> const& media,
         MeshLib::PropertyVector<int> const* const material_ids)
-        : _media(media), _material_ids(material_ids)
+        : media_(media), material_ids_(material_ids)
     {
     }
 
@@ -40,7 +40,7 @@ public:
     void checkElementHasMedium(std::size_t const element_id);
 
 private:
-    std::map<int, std::shared_ptr<Medium>> const& _media;
-    MeshLib::PropertyVector<int> const* const _material_ids;
+    std::map<int, std::shared_ptr<Medium>> const& media_;
+    MeshLib::PropertyVector<int> const* const material_ids_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Medium.cpp b/MaterialLib/MPL/Medium.cpp
index 323c2dfda43e91fb0a247be5c3ec87175e954161..1527c1372d2c4c5daf0690ef2109da12ac8bc23d 100644
--- a/MaterialLib/MPL/Medium.cpp
+++ b/MaterialLib/MPL/Medium.cpp
@@ -19,23 +19,23 @@ namespace MaterialPropertyLib
 {
 Medium::Medium(std::vector<std::unique_ptr<Phase>>&& phases,
                std::unique_ptr<PropertyArray>&& properties)
-    : _phases(std::move(phases))
+    : phases_(std::move(phases))
 {
     if (properties)
     {
-        overwriteExistingProperties(_properties, *properties, this);
+        overwriteExistingProperties(properties_, *properties, this);
     }
 }
 
 Phase const& Medium::phase(std::size_t const index) const
 {
-    return *_phases[index];
+    return *phases_[index];
 }
 
 Phase const& Medium::phase(std::string const& name) const
 {
     return *BaseLib::findElementOrError(
-        _phases.begin(), _phases.end(),
+        phases_.begin(), phases_.end(),
         [&name](std::unique_ptr<MaterialPropertyLib::Phase> const& phase) {
             return phase->name == name;
         },
@@ -44,16 +44,16 @@ Phase const& Medium::phase(std::string const& name) const
 
 Property const& Medium::property(PropertyType const& p) const
 {
-    return *_properties[p];
+    return *properties_[p];
 }
 
 bool Medium::hasProperty(PropertyType const& p) const
 {
-    return _properties[p] != nullptr;
+    return properties_[p] != nullptr;
 }
 
 std::size_t Medium::numberOfPhases() const
 {
-    return _phases.size();
+    return phases_.size();
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Medium.h b/MaterialLib/MPL/Medium.h
index fc7da58643bd4c5903458fcf2243b293640d7558..8cec072d86e66cb3b29dbfa4b85cc3887fadbc19 100644
--- a/MaterialLib/MPL/Medium.h
+++ b/MaterialLib/MPL/Medium.h
@@ -34,7 +34,7 @@ public:
            std::unique_ptr<PropertyArray>&& properties);
 
     /// A get-function for a particular phase. The ul argument specifies the
-    /// index within the _phases vector.
+    /// index within the phases_ vector.
     Phase const& phase(std::size_t index) const;
     /// A get-function for a particular phase by phase name.
     Phase const& phase(std::string const& phase_name) const;
@@ -79,14 +79,14 @@ public:
 
 private:
     /// The vector that holds the phases.
-    std::vector<std::unique_ptr<Phase>> const _phases;
+    std::vector<std::unique_ptr<Phase>> const phases_;
     /// The array that holds the medium properties.
     ///
     /// Currently, these defaults is the volume fraction average.
     ///
     /// Most properties are fine with the volume fraction average, but
     /// special-defaults are allowed as well...
-    PropertyArray _properties;
+    PropertyArray properties_;
 };
 
 template <typename Container>
diff --git a/MaterialLib/MPL/Phase.cpp b/MaterialLib/MPL/Phase.cpp
index 4aa9cf7b488afa6264159a251529df9f3606f07f..75cbdf3ff49bb39c8f92b60179ae55c25c6837c8 100644
--- a/MaterialLib/MPL/Phase.cpp
+++ b/MaterialLib/MPL/Phase.cpp
@@ -21,28 +21,28 @@ namespace MaterialPropertyLib
 Phase::Phase(std::string&& phase_name,
              std::vector<std::unique_ptr<Component>>&& components,
              std::unique_ptr<PropertyArray>&& properties)
-    : name(std::move(phase_name)), _components(std::move(components))
+    : name(std::move(phase_name)), components_(std::move(components))
 {
     if (properties)
     {
-        overwriteExistingProperties(_properties, *properties, this);
+        overwriteExistingProperties(properties_, *properties, this);
     }
 }
 
 Component const& Phase::component(const std::size_t& index) const
 {
-    return *_components[index];
+    return *components_[index];
 }
 
 bool Phase::hasComponent(std::size_t const& index) const
 {
-    return _components[index] != nullptr;
+    return components_[index] != nullptr;
 }
 
 Component const& Phase::component(std::string const& name) const
 {
     return *BaseLib::findElementOrError(
-        _components.begin(), _components.end(),
+        components_.begin(), components_.end(),
         [&name](std::unique_ptr<Component> const& component) {
             return component->name == name;
         },
@@ -51,17 +51,17 @@ Component const& Phase::component(std::string const& name) const
 
 Property const& Phase::property(PropertyType const& p) const
 {
-    return *_properties[p];
+    return *properties_[p];
 }
 
 bool Phase::hasProperty(PropertyType const& p) const
 {
-    return _properties[p] != nullptr;
+    return properties_[p] != nullptr;
 }
 
 std::size_t Phase::numberOfComponents() const
 {
-    return _components.size();
+    return components_.size();
 }
 
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Phase.h b/MaterialLib/MPL/Phase.h
index 576e7d2d47d03a86e251d248d4bb20123f047677..0efa37f6558727ea449f32c3d8f1332bd16cf131 100644
--- a/MaterialLib/MPL/Phase.h
+++ b/MaterialLib/MPL/Phase.h
@@ -55,14 +55,14 @@ public:
     std::string const name;
 
 private:
-    std::vector<std::unique_ptr<Component>> const _components;
+    std::vector<std::unique_ptr<Component>> const components_;
 
     /// Here, all for all properties listed in the Properties enumerator are
     /// initialized by mole average functions of value zero. However,
     /// 'special-default' properties are allowed to be set.
     ///
     /// After this, other special properties can be set as exceptional defaults.
-    PropertyArray _properties;
+    PropertyArray properties_;
 };
 
 template <typename Container>
diff --git a/MaterialLib/MPL/Properties/BishopsPowerLaw.cpp b/MaterialLib/MPL/Properties/BishopsPowerLaw.cpp
index 069d861dfd03fdd8b430f9d6879523550a24ed33..f4d310cf8b17b619e3b064f0580dcd23c731187f 100644
--- a/MaterialLib/MPL/Properties/BishopsPowerLaw.cpp
+++ b/MaterialLib/MPL/Properties/BishopsPowerLaw.cpp
@@ -11,7 +11,7 @@
 
 namespace MaterialPropertyLib
 {
-BishopsPowerLaw::BishopsPowerLaw(double const exponent) : _m(exponent) {}
+BishopsPowerLaw::BishopsPowerLaw(double const exponent) : m_(exponent) {}
 
 void BishopsPowerLaw::setScale(
     std::variant<Medium*, Phase*, Component*> scale_pointer)
@@ -22,7 +22,7 @@ void BishopsPowerLaw::setScale(
             "The property 'BishopsPowerLaw' is implemented on the 'media' "
             "scale only.");
     }
-    _medium = std::get<Medium*>(scale_pointer);
+    medium_ = std::get<Medium*>(scale_pointer);
 }
 
 PropertyDataType BishopsPowerLaw::value(
@@ -33,7 +33,7 @@ PropertyDataType BishopsPowerLaw::value(
     auto const S_L = std::get<double>(
         variable_array[static_cast<int>(Variable::liquid_saturation)]);
 
-    return std::pow(S_L, _m);
+    return std::pow(S_L, m_);
 }
 
 PropertyDataType BishopsPowerLaw::dValue(
@@ -49,6 +49,6 @@ PropertyDataType BishopsPowerLaw::dValue(
     auto const S_L = std::get<double>(
         variable_array[static_cast<int>(Variable::liquid_saturation)]);
 
-    return _m * std::pow(S_L, _m - 1.);
+    return m_ * std::pow(S_L, m_ - 1.);
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/BishopsPowerLaw.h b/MaterialLib/MPL/Properties/BishopsPowerLaw.h
index bee26d4d2693d9ef0e953ca52a71c56df15ee629..c75b8d33cc1ece82b7391479610f3b390e7fbe76 100644
--- a/MaterialLib/MPL/Properties/BishopsPowerLaw.h
+++ b/MaterialLib/MPL/Properties/BishopsPowerLaw.h
@@ -32,7 +32,7 @@ public:
                             double const /*dt*/) const override;
 
 private:
-    Medium* _medium = nullptr;
-    double const _m;  //< Exponent.
+    Medium* medium_ = nullptr;
+    double const m_;  //< Exponent.
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/BishopsSaturationCutoff.cpp b/MaterialLib/MPL/Properties/BishopsSaturationCutoff.cpp
index 8e25999e41531aa78727dbcf90bce25e3f813b80..f237e6677acac11a2f61358de5b11abe108ea709 100644
--- a/MaterialLib/MPL/Properties/BishopsSaturationCutoff.cpp
+++ b/MaterialLib/MPL/Properties/BishopsSaturationCutoff.cpp
@@ -12,7 +12,7 @@
 namespace MaterialPropertyLib
 {
 BishopsSaturationCutoff::BishopsSaturationCutoff(double const cutoff_value)
-    : _S_L_max(cutoff_value)
+    : S_L_max_(cutoff_value)
 {
 }
 
@@ -25,7 +25,7 @@ void BishopsSaturationCutoff::setScale(
             "The property 'BishopsSaturationCutoff' is implemented on the "
             "'media' scale only.");
     }
-    _medium = std::get<Medium*>(scale_pointer);
+    medium_ = std::get<Medium*>(scale_pointer);
 }
 
 PropertyDataType BishopsSaturationCutoff::value(
@@ -36,7 +36,7 @@ PropertyDataType BishopsSaturationCutoff::value(
     auto const S_L = std::get<double>(
         variable_array[static_cast<int>(Variable::liquid_saturation)]);
 
-    return S_L < _S_L_max ? 0. : 1.;
+    return S_L < S_L_max_ ? 0. : 1.;
 }
 
 PropertyDataType BishopsSaturationCutoff::dValue(
diff --git a/MaterialLib/MPL/Properties/BishopsSaturationCutoff.h b/MaterialLib/MPL/Properties/BishopsSaturationCutoff.h
index fff74493adcae40faa0fa88a23ddb7f486532c26..17f298963a625cc8926599b59c8ab4dedc55d446 100644
--- a/MaterialLib/MPL/Properties/BishopsSaturationCutoff.h
+++ b/MaterialLib/MPL/Properties/BishopsSaturationCutoff.h
@@ -34,7 +34,7 @@ public:
                             double const /*dt*/) const override;
 
 private:
-    Medium* _medium = nullptr;
-    double const _S_L_max;  //< Maximum saturation cutoff value.
+    Medium* medium_ = nullptr;
+    double const S_L_max_;  //< Maximum saturation cutoff value.
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.cpp b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.cpp
index 31cde588bb8b4e82d9e4446a047ee131f7c3ebeb..c39dd4c57860e5a0185f49fad60454ae557dea77 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.cpp
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.cpp
@@ -24,57 +24,57 @@ CapillaryPressureVanGenuchten::CapillaryPressureVanGenuchten(
     double const exponent,
     double const p_b,
     double const maximum_capillary_pressure)
-    : _S_L_res(residual_liquid_saturation),
-      _S_L_max(1. - residual_gas_saturation),
-      _m(exponent),
-      _p_b(p_b),
-      _p_cap_max(maximum_capillary_pressure)
+    : S_L_res_(residual_liquid_saturation),
+      S_L_max_(1. - residual_gas_saturation),
+      m_(exponent),
+      p_b_(p_b),
+      p_cap_max_(maximum_capillary_pressure)
 {
-    if (_S_L_res < 0 || _S_L_res > 1)
+    if (S_L_res_ < 0 || S_L_res_ > 1)
     {
         OGS_FATAL(
             "Van Genuchten capillary pressure model: "
             "The residual liquid saturation value S_L_res = {:g} is out of "
             "admissible range [0, 1].",
-            _S_L_res);
+            S_L_res_);
     }
-    if (_S_L_max < 0 || _S_L_max > 1)
+    if (S_L_max_ < 0 || S_L_max_ > 1)
     {
         OGS_FATAL(
             "Van Genuchten capillary pressure model: "
             "The maximum liquid saturation value S_L_max = {:g} is out of "
             "admissible range [0, 1].",
-            _S_L_max);
+            S_L_max_);
     }
-    if (_S_L_res >= _S_L_max)
+    if (S_L_res_ >= S_L_max_)
     {
         OGS_FATAL(
             "Van Genuchten capillary pressure model: "
             "The maximum liquid saturation S_L_max = {:g} must not be less or "
             "equal to the residual liquid saturion S_L_res = { : g}.",
-            _S_L_max, _S_L_res);
+            S_L_max_, S_L_res_);
     }
-    if (!(_m > 0 && _m < 1))
+    if (!(m_ > 0 && m_ < 1))
     {
         OGS_FATAL(
             "Van Genuchten capillary pressure model: "
             "The exponent value m = {:g} is out of of admissible range (0, 1).",
-            _m);
+            m_);
     }
-    if (_p_b <= 0)
+    if (p_b_ <= 0)
     {
         OGS_FATAL(
             "Van Genuchten capillary pressure model: "
             "The pressure scaling value p_b = {:g} must be positive.",
-            _p_b);
+            p_b_);
     }
-    if (_p_cap_max < 0)
+    if (p_cap_max_ < 0)
     {
         OGS_FATAL(
             "Van Genuchten capillary pressure model: "
             "The maximum capillary pressure value p_cap_max = {:g} must be "
             "non-negative.",
-            _p_cap_max);
+            p_cap_max_);
     }
 }
 
@@ -86,23 +86,23 @@ PropertyDataType CapillaryPressureVanGenuchten::value(
     double const S_L = std::get<double>(
         variable_array[static_cast<int>(Variable::liquid_saturation)]);
 
-    if (S_L <= _S_L_res)
+    if (S_L <= S_L_res_)
     {
-        return _p_cap_max;
+        return p_cap_max_;
     }
 
-    if (S_L >= _S_L_max)
+    if (S_L >= S_L_max_)
     {
         return 0;
     }
 
-    double const S_eff = (S_L - _S_L_res) / (_S_L_max - _S_L_res);
+    double const S_eff = (S_L - S_L_res_) / (S_L_max_ - S_L_res_);
     assert(0 <= S_eff && S_eff <= 1);
 
     double const p_cap =
-        _p_b * std::pow(std::pow(S_eff, -1.0 / _m) - 1.0, 1.0 - _m);
+        p_b_ * std::pow(std::pow(S_eff, -1.0 / m_) - 1.0, 1.0 - m_);
     assert(p_cap > 0);
-    return std::min(p_cap, _p_cap_max);
+    return std::min(p_cap, p_cap_max_);
 }
 
 PropertyDataType CapillaryPressureVanGenuchten::dValue(
@@ -118,28 +118,28 @@ PropertyDataType CapillaryPressureVanGenuchten::dValue(
     double const S_L = std::get<double>(
         variable_array[static_cast<int>(Variable::liquid_saturation)]);
 
-    if (S_L <= _S_L_res)
+    if (S_L <= S_L_res_)
     {
         return 0;
     }
 
-    if (S_L >= _S_L_max)
+    if (S_L >= S_L_max_)
     {
         return 0;
     }
 
-    double const S_eff = (S_L - _S_L_res) / (_S_L_max - _S_L_res);
+    double const S_eff = (S_L - S_L_res_) / (S_L_max_ - S_L_res_);
 
     assert(0 < S_eff && S_eff < 1.0);
 
-    double const val1 = std::pow(S_eff, -1.0 / _m);
-    double const p_cap = _p_b * std::pow(val1 - 1.0, 1.0 - _m);
-    if (p_cap >= _p_cap_max)
+    double const val1 = std::pow(S_eff, -1.0 / m_);
+    double const p_cap = p_b_ * std::pow(val1 - 1.0, 1.0 - m_);
+    if (p_cap >= p_cap_max_)
     {
         return 0;
     }
 
-    double const val2 = std::pow(val1 - 1.0, -_m);
-    return _p_b * (_m - 1.0) * val1 * val2 / (_m * (S_L - _S_L_res));
+    double const val2 = std::pow(val1 - 1.0, -m_);
+    return p_b_ * (m_ - 1.0) * val1 * val2 / (m_ * (S_L - S_L_res_));
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.h b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.h
index 3538d3828fc99fa3095e3fe4dc7c37bb94ccba28..efe686be492e7cdeeda96f99714a7cbc3ac40d09 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.h
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/CapillaryPressureVanGenuchten.h
@@ -57,7 +57,7 @@ public:
                 "The property 'CapillaryPressureVanGenuchten' is implemented "
                 "on the 'media' scale only.");
         }
-        _medium = std::get<Medium*>(scale_pointer);
+        medium_ = std::get<Medium*>(scale_pointer);
     }
 
     /// \returns \f$ p_c(S) \f$.
@@ -74,11 +74,11 @@ public:
                             double const dt) const override;
 
 private:
-    Medium* _medium = nullptr;
-    double const _S_L_res;    ///< Residual saturation of liquid phase.
-    double const _S_L_max;    ///< Maximum saturation of liquid phase.
-    double const _m;          ///< Exponent.
-    double const _p_b;        ///< Pressure scaling factor.
-    double const _p_cap_max;  ///< Maximum capillary pressure.
+    Medium* medium_ = nullptr;
+    double const S_L_res_;    ///< Residual saturation of liquid phase.
+    double const S_L_max_;    ///< Maximum saturation of liquid phase.
+    double const m_;          ///< Exponent.
+    double const p_b_;        ///< Pressure scaling factor.
+    double const p_cap_max_;  ///< Maximum capillary pressure.
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.cpp b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.cpp
index d570ff7ac1c81f2946990c321e0adf3d624fbc27..688bf54d44f6f9f8a45b6060dc32ec10708ba0a8 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.cpp
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.cpp
@@ -27,10 +27,10 @@ SaturationBrooksCorey::SaturationBrooksCorey(
     const double residual_gas_saturation,
     const double exponent,
     const double entry_pressure)
-    : _residual_liquid_saturation(residual_liquid_saturation),
-      _residual_gas_saturation(residual_gas_saturation),
-      _exponent(exponent),
-      _entry_pressure(entry_pressure){};
+    : residual_liquid_saturation_(residual_liquid_saturation),
+      residual_gas_saturation_(residual_gas_saturation),
+      exponent_(exponent),
+      entry_pressure_(entry_pressure){};
 
 PropertyDataType SaturationBrooksCorey::value(
     VariableArray const& variable_array,
@@ -40,10 +40,10 @@ PropertyDataType SaturationBrooksCorey::value(
     const double p_cap = std::get<double>(
         variable_array[static_cast<int>(Variable::capillary_pressure)]);
 
-    const double s_L_res = _residual_liquid_saturation;
-    const double s_L_max = 1.0 - _residual_gas_saturation;
-    const double lambda = _exponent;
-    const double p_b = _entry_pressure;
+    const double s_L_res = residual_liquid_saturation_;
+    const double s_L_max = 1.0 - residual_gas_saturation_;
+    const double lambda = exponent_;
+    const double p_b = entry_pressure_;
 
     if (p_cap <= p_b)
         return s_L_max;
@@ -62,18 +62,18 @@ PropertyDataType SaturationBrooksCorey::dValue(
            "SaturationBrooksCorey::dValue is implemented for "
            " derivatives with respect to capillary pressure only.");
 
-    const double s_L_res = _residual_liquid_saturation;
-    const double s_L_max = 1.0 - _residual_gas_saturation;
-    const double p_b = _entry_pressure;
+    const double s_L_res = residual_liquid_saturation_;
+    const double s_L_max = 1.0 - residual_gas_saturation_;
+    const double p_b = entry_pressure_;
     const double p_cap = std::max(
         p_b,
         std::get<double>(
             variable_array[static_cast<int>(Variable::capillary_pressure)]));
 
-    auto const s_L = _medium->property(PropertyType::saturation)
+    auto const s_L = medium_->property(PropertyType::saturation)
                          .template value<double>(variable_array, pos, t, dt);
 
-    const double lambda = _exponent;
+    const double lambda = exponent_;
     const double ds_L_d_s_eff = 1. / (s_L_max - s_L_res);
 
     return -lambda / p_cap * s_L * ds_L_d_s_eff;
@@ -92,16 +92,16 @@ PropertyDataType SaturationBrooksCorey::d2Value(
            "SaturationBrooksCorey::d2Value is implemented for "
            " derivatives with respect to capillary pressure only.");
 
-    const double p_b = _entry_pressure;
+    const double p_b = entry_pressure_;
     const double p_cap = std::max(
         p_b,
         std::get<double>(
             variable_array[static_cast<int>(Variable::capillary_pressure)]));
 
-    const double s_L_res = _residual_liquid_saturation;
-    const double s_L_max = 1.0 - _residual_gas_saturation;
+    const double s_L_res = residual_liquid_saturation_;
+    const double s_L_max = 1.0 - residual_gas_saturation_;
 
-    const double lambda = _exponent;
+    const double lambda = exponent_;
 
     return lambda * (lambda + 1) * std::pow(p_b / p_cap, lambda) /
            (p_cap * p_cap) * (s_L_max - s_L_res);
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.h b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.h
index 56e21849d29fab01b9b9d702b37a7e21436a5b20..4c6ba62ed0521dcc83cf38de8c81a642fde7dc21 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.h
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationBrooksCorey.h
@@ -30,11 +30,11 @@ class Component;
 class SaturationBrooksCorey final : public Property
 {
 private:
-    Medium* _medium = nullptr;
-    const double _residual_liquid_saturation;
-    const double _residual_gas_saturation;
-    const double _exponent;
-    const double _entry_pressure;
+    Medium* medium_ = nullptr;
+    const double residual_liquid_saturation_;
+    const double residual_gas_saturation_;
+    const double exponent_;
+    const double entry_pressure_;
 
 public:
     SaturationBrooksCorey(const double residual_liquid_saturation,
@@ -51,11 +51,11 @@ public:
                 "The property 'SaturationBrooksCorey' is implemented on the "
                 "'media' scale only.");
         }
-        _medium = std::get<Medium*>(scale_pointer);
+        medium_ = std::get<Medium*>(scale_pointer);
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& /*pos*/,
                            double const /*t*/,
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.cpp b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.cpp
index cb71c908b4546d94d768125113af42862d55e747..dc44cdf98da7f9db36bed9a90e9af9418bb6b33a 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.cpp
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.cpp
@@ -33,8 +33,8 @@ PropertyDataType SaturationLiakopoulos::value(
     if (p_cap < 0.)
         return 1.;
 
-    return std::max(_residual_liquid_saturation,
-                    1. - _parameter_a * std::pow(p_cap, _parameter_b));
+    return std::max(residual_liquid_saturation_,
+                    1. - parameter_a_ * std::pow(p_cap, parameter_b_));
 }
 
 PropertyDataType SaturationLiakopoulos::dValue(
@@ -53,10 +53,10 @@ PropertyDataType SaturationLiakopoulos::dValue(
     {
         return 0.;
     }
-    const double p_cap_restricted = std::min(p_cap, _p_cap_max);
+    const double p_cap_restricted = std::min(p_cap, p_cap_max_);
 
-    return -_parameter_a * _parameter_b *
-           std::pow(p_cap_restricted, _parameter_b - 1.);
+    return -parameter_a_ * parameter_b_ *
+           std::pow(p_cap_restricted, parameter_b_ - 1.);
 }
 
 PropertyDataType SaturationLiakopoulos::d2Value(
@@ -79,9 +79,9 @@ PropertyDataType SaturationLiakopoulos::d2Value(
     {
         return 0.;
     }
-    const double p_cap_restricted = std::min(p_cap, _p_cap_max);
-    return -_parameter_a * (_parameter_b - 1.) * _parameter_b *
-           std::pow(p_cap_restricted, _parameter_b - 2.);
+    const double p_cap_restricted = std::min(p_cap, p_cap_max_);
+    return -parameter_a_ * (parameter_b_ - 1.) * parameter_b_ *
+           std::pow(p_cap_restricted, parameter_b_ - 2.);
 }
 
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.h b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.h
index 87ea80a15c18563411bc1bdb0b6e7aa67b351758..6676cb27803d4bde125f497e1086c057bebf809b 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.h
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationLiakopoulos.h
@@ -36,7 +36,7 @@ class Component;
 class SaturationLiakopoulos final : public Property
 {
 private:
-    Medium* _medium = nullptr;
+    Medium* medium_ = nullptr;
     /**
       Parameters for Liakopoulos saturation curve taken from:
       Asadi, R., Ataie-Ashtiani, B. (2015): A Comparison of finite volume
@@ -46,11 +46,11 @@ private:
       Those parameters are fixed for that particular model, no need to change
       them.
     */
-    const double _residual_liquid_saturation = 0.2;
-    const double _parameter_a = 1.9722e-11;
-    const double _parameter_b = 2.4279;
-    const double _p_cap_max = std::pow(
-        (1. - _residual_liquid_saturation) / _parameter_a, (1. / _parameter_b));
+    const double residual_liquid_saturation_ = 0.2;
+    const double parameter_a_ = 1.9722e-11;
+    const double parameter_b_ = 2.4279;
+    const double p_cap_max_ = std::pow(
+        (1. - residual_liquid_saturation_) / parameter_a_, (1. / parameter_b_));
 
 public:
     /// This method assigns a pointer to the material object that is the owner
@@ -60,7 +60,7 @@ public:
     {
         if (std::holds_alternative<Medium*>(scale_pointer))
         {
-            _medium = std::get<Medium*>(scale_pointer);
+            medium_ = std::get<Medium*>(scale_pointer);
         }
         else
         {
@@ -71,7 +71,7 @@ public:
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& /*pos*/,
                            double const /*t*/,
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.cpp b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.cpp
index c87bec41a0feadfcb8b481eba457dda4847e2128..4aa4d3a95c305120540bbd307b0e78614592252b 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.cpp
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.cpp
@@ -22,17 +22,17 @@ SaturationVanGenuchten::SaturationVanGenuchten(
     double const residual_gas_saturation,
     double const exponent,
     double const p_b)
-    : _S_L_res(residual_liquid_saturation),
-      _S_L_max(1. - residual_gas_saturation),
-      _m(exponent),
-      _p_b(p_b)
+    : S_L_res_(residual_liquid_saturation),
+      S_L_max_(1. - residual_gas_saturation),
+      m_(exponent),
+      p_b_(p_b)
 {
-    if (!(_m > 0 && _m < 1))
+    if (!(m_ > 0 && m_ < 1))
     {
         OGS_FATAL(
             "The exponent value m = {:g} of van Genuchten saturation model, is "
             "out of its range of (0, 1)",
-            _m);
+            m_);
     }
 }
 
@@ -46,16 +46,16 @@ PropertyDataType SaturationVanGenuchten::value(
 
     if (p_cap <= 0)
     {
-        return _S_L_max;
+        return S_L_max_;
     }
 
-    double const p = p_cap / _p_b;
-    double const n = 1. / (1. - _m);
+    double const p = p_cap / p_b_;
+    double const n = 1. / (1. - m_);
     double const p_to_n = std::pow(p, n);
 
-    double const S_eff = std::pow(p_to_n + 1., -_m);
-    double const S = S_eff * _S_L_max - S_eff * _S_L_res + _S_L_res;
-    return std::clamp(S, _S_L_res, _S_L_max);
+    double const S_eff = std::pow(p_to_n + 1., -m_);
+    double const S = S_eff * S_L_max_ - S_eff * S_L_res_ + S_L_res_;
+    return std::clamp(S, S_L_res_, S_L_max_);
 }
 
 PropertyDataType SaturationVanGenuchten::dValue(
@@ -76,22 +76,22 @@ PropertyDataType SaturationVanGenuchten::dValue(
         return 0;
     }
 
-    double const p = p_cap / _p_b;
-    double const n = 1. / (1. - _m);
+    double const p = p_cap / p_b_;
+    double const n = 1. / (1. - m_);
     double const p_to_n = std::pow(p, n);
 
-    double const S_eff = std::pow(p_to_n + 1., -_m);
-    double const S = S_eff * _S_L_max - S_eff * _S_L_res + _S_L_res;
+    double const S_eff = std::pow(p_to_n + 1., -m_);
+    double const S = S_eff * S_L_max_ - S_eff * S_L_res_ + S_L_res_;
 
-    if (S < _S_L_res || S > _S_L_max)
+    if (S < S_L_res_ || S > S_L_max_)
     {
         return 0;
     }
 
-    double const dS_eff_dp_cap = -_m * std::pow(p_cap / _p_b, n - 1) *
-                                 std::pow(1 + p_to_n, -1. - _m) /
-                                 (_p_b * (1. - _m));
-    return dS_eff_dp_cap * (_S_L_max - _S_L_res);
+    double const dS_eff_dp_cap = -m_ * std::pow(p_cap / p_b_, n - 1) *
+                                 std::pow(1 + p_to_n, -1. - m_) /
+                                 (p_b_ * (1. - m_));
+    return dS_eff_dp_cap * (S_L_max_ - S_L_res_);
 }
 
 PropertyDataType SaturationVanGenuchten::d2Value(
@@ -115,21 +115,21 @@ PropertyDataType SaturationVanGenuchten::d2Value(
         return 0;
     }
 
-    double const p = p_cap / _p_b;
-    double const n = 1. / (1. - _m);
+    double const p = p_cap / p_b_;
+    double const n = 1. / (1. - m_);
     double const p_to_n = std::pow(p, n);
 
-    double const S_eff = std::pow(p_to_n + 1., -_m);
-    double const S = S_eff * _S_L_max - S_eff * _S_L_res + _S_L_res;
+    double const S_eff = std::pow(p_to_n + 1., -m_);
+    double const S = S_eff * S_L_max_ - S_eff * S_L_res_ + S_L_res_;
 
-    if (S < _S_L_res || S > _S_L_max)
+    if (S < S_L_res_ || S > S_L_max_)
     {
         return 0;
     }
 
     double const d2S_eff_dp_cap2 =
-        _m * p_to_n * std::pow(p_to_n + 1., -_m - 2.) * (p_to_n - _m) /
-        (p_cap * p_cap * (_m - 1.) * (_m - 1.));
-    return d2S_eff_dp_cap2 * (_S_L_max - _S_L_res);
+        m_ * p_to_n * std::pow(p_to_n + 1., -m_ - 2.) * (p_to_n - m_) /
+        (p_cap * p_cap * (m_ - 1.) * (m_ - 1.));
+    return d2S_eff_dp_cap2 * (S_L_max_ - S_L_res_);
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.h b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.h
index 6590f22b6aeff9bfae8ddbf93d415e5dd11b6b6f..2e39d848cfab27e6899a712668dfcb83d1f75fe8 100644
--- a/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.h
+++ b/MaterialLib/MPL/Properties/CapillaryPressureSaturation/SaturationVanGenuchten.h
@@ -60,11 +60,11 @@ public:
                 "The property 'SaturationVanGenuchten' is implemented on the "
                 "'media' scale only.");
         }
-        _medium = std::get<Medium*>(scale_pointer);
+        medium_ = std::get<Medium*>(scale_pointer);
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& /*pos*/,
                            double const /*t*/,
@@ -81,10 +81,10 @@ public:
                              double const /*dt*/) const override;
 
 private:
-    Medium* _medium = nullptr;
-    double const _S_L_res;
-    double const _S_L_max;
-    double const _m;
-    double const _p_b;
+    Medium* medium_ = nullptr;
+    double const S_L_res_;
+    double const S_L_max_;
+    double const m_;
+    double const p_b_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/Constant.cpp b/MaterialLib/MPL/Properties/Constant.cpp
index d0e5a71c9f7facf256b27b156f6f69420f3b0ae5..7aca20c209fbbc417fec02f99acc1223cf527eef 100644
--- a/MaterialLib/MPL/Properties/Constant.cpp
+++ b/MaterialLib/MPL/Properties/Constant.cpp
@@ -16,8 +16,8 @@ namespace MaterialPropertyLib
 {
 Constant::Constant(PropertyDataType const& v)
 {
-    _value = v;
-    _dvalue = std::visit(
+    value_ = v;
+    dvalue_ = std::visit(
         [](auto const& value) -> PropertyDataType { return decltype(value){}; },
         v);
 };
diff --git a/MaterialLib/MPL/Properties/Constant.h b/MaterialLib/MPL/Properties/Constant.h
index 268d949bd54ea9d2332d7121f0b0994c5d531689..15424fa71921efb7a3df5045d22ead24b6ca4922 100644
--- a/MaterialLib/MPL/Properties/Constant.h
+++ b/MaterialLib/MPL/Properties/Constant.h
@@ -22,7 +22,7 @@ class Constant final : public Property
 {
 public:
     /// This constructor accepts single values of any data type defined in the
-    /// PropertyDataType definition and sets the protected attribute _value of
+    /// PropertyDataType definition and sets the protected attribute value_ of
     /// the base class Property to that value.
     explicit Constant(PropertyDataType const& v);
 };
diff --git a/MaterialLib/MPL/Properties/CurveProperty.cpp b/MaterialLib/MPL/Properties/CurveProperty.cpp
index d7da60327ec17de2cb77cb2238449cbe6bc58dd1..a6deb4ae28f4e2b1f3b70e6b9097ee3228c44a40 100644
--- a/MaterialLib/MPL/Properties/CurveProperty.cpp
+++ b/MaterialLib/MPL/Properties/CurveProperty.cpp
@@ -14,7 +14,7 @@ namespace MaterialPropertyLib
 {
 CurveProperty::CurveProperty(Variable const independent_variable,
                              MathLib::PiecewiseLinearInterpolation const& curve)
-    : _independent_variable(independent_variable), _curve(curve)
+    : independent_variable_(independent_variable), curve_(curve)
 {
 }
 
@@ -24,8 +24,8 @@ PropertyDataType CurveProperty::value(
     double const /*dt*/) const
 {
     auto const x = std::get<double>(
-        variable_array[static_cast<int>(_independent_variable)]);
-    return _curve.getValue(x);
+        variable_array[static_cast<int>(independent_variable_)]);
+    return curve_.getValue(x);
 }
 
 PropertyDataType CurveProperty::dValue(
@@ -35,7 +35,7 @@ PropertyDataType CurveProperty::dValue(
     double const /*dt*/) const
 {
     auto const x = std::get<double>(
-        variable_array[static_cast<int>(_independent_variable)]);
-    return _curve.getDerivative(x);
+        variable_array[static_cast<int>(independent_variable_)]);
+    return curve_.getDerivative(x);
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/CurveProperty.h b/MaterialLib/MPL/Properties/CurveProperty.h
index a6174157983684791fbf66877daba24766783b76..7762125586b512fb31091e38d8e4ca8deef288fc 100644
--- a/MaterialLib/MPL/Properties/CurveProperty.h
+++ b/MaterialLib/MPL/Properties/CurveProperty.h
@@ -44,8 +44,8 @@ public:
 
 private:
     /// The variable type that the curve property depends on.
-    Variable const _independent_variable;
+    Variable const independent_variable_;
     /// The curve used by the property.
-    MathLib::PiecewiseLinearInterpolation const& _curve;
+    MathLib::PiecewiseLinearInterpolation const& curve_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/DupuitPermeability.cpp b/MaterialLib/MPL/Properties/DupuitPermeability.cpp
index 70263dc7edc5f7b8c69cdd7d82a35c18abfd4783..9c65b2ce043ffdf4d6c143225b49cbe1a1642584 100644
--- a/MaterialLib/MPL/Properties/DupuitPermeability.cpp
+++ b/MaterialLib/MPL/Properties/DupuitPermeability.cpp
@@ -14,7 +14,7 @@ namespace MaterialPropertyLib
 {
 DupuitPermeability::DupuitPermeability(
     ParameterLib::Parameter<double> const& parameter)
-    : _parameter(parameter)
+    : parameter_(parameter)
 {
 }
 
@@ -25,7 +25,7 @@ PropertyDataType DupuitPermeability::value(
 {
     double const pressure = std::get<double>(variable_array[static_cast<int>(
         MaterialPropertyLib::Variable::phase_pressure)]);
-    auto const& permeability_values = _parameter(t, pos);
+    auto const& permeability_values = parameter_(t, pos);
 
     auto const& permeability_variant = fromVector(permeability_values);
     PropertyDataType dupuit_permeability = std::visit(
diff --git a/MaterialLib/MPL/Properties/DupuitPermeability.h b/MaterialLib/MPL/Properties/DupuitPermeability.h
index 2cc576c665541d41df3a34c0d4bfddc457b95c71..fbec1686dbd9b91eb0e1819332be623bc50e939e 100644
--- a/MaterialLib/MPL/Properties/DupuitPermeability.h
+++ b/MaterialLib/MPL/Properties/DupuitPermeability.h
@@ -31,6 +31,6 @@ public:
         double const dt) const override;
 
 private:
-    ParameterLib::Parameter<double> const& _parameter;
+    ParameterLib::Parameter<double> const& parameter_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/ExponentialProperty.cpp b/MaterialLib/MPL/Properties/ExponentialProperty.cpp
index c1047231fa1033792ab58baa1cf9836e3ca4a05c..e13a40a034b62c5015b0ffd9eb474665e247156a 100644
--- a/MaterialLib/MPL/Properties/ExponentialProperty.cpp
+++ b/MaterialLib/MPL/Properties/ExponentialProperty.cpp
@@ -17,9 +17,9 @@ namespace MaterialPropertyLib
 {
 ExponentialProperty::ExponentialProperty(
     PropertyDataType const& property_reference_value, ExponentData const& v)
-    : _exponent_data(v)
+    : exponent_data_(v)
 {
-    _value = property_reference_value;
+    value_ = property_reference_value;
 }
 
 PropertyDataType ExponentialProperty::value(
@@ -27,12 +27,12 @@ PropertyDataType ExponentialProperty::value(
     ParameterLib::SpatialPosition const& /*pos*/, double const /*t*/,
     double const /*dt*/) const
 {
-    return std::get<double>(_value) *
+    return std::get<double>(value_) *
            std::exp(
-               -std::get<double>(_exponent_data.factor) *
+               -std::get<double>(exponent_data_.factor) *
                (std::get<double>(
-                    variable_array[static_cast<int>(_exponent_data.type)]) -
-                std::get<double>(_exponent_data.reference_condition)));
+                    variable_array[static_cast<int>(exponent_data_.type)]) -
+                std::get<double>(exponent_data_.reference_condition)));
 }
 
 PropertyDataType ExponentialProperty::dValue(
@@ -40,15 +40,15 @@ PropertyDataType ExponentialProperty::dValue(
     ParameterLib::SpatialPosition const& /*pos*/, double const /*t*/,
     double const /*dt*/) const
 {
-    return _exponent_data.type == primary_variable
-               ? -std::get<double>(_value) *
-                     std::get<double>(_exponent_data.factor) *
+    return exponent_data_.type == primary_variable
+               ? -std::get<double>(value_) *
+                     std::get<double>(exponent_data_.factor) *
                      std::exp(
-                         -std::get<double>(_exponent_data.factor) *
+                         -std::get<double>(exponent_data_.factor) *
                          (std::get<double>(variable_array[static_cast<int>(
-                              _exponent_data.type)]) -
-                          std::get<double>(_exponent_data.reference_condition)))
-               : decltype(_value){};
+                              exponent_data_.type)]) -
+                          std::get<double>(exponent_data_.reference_condition)))
+               : decltype(value_){};
 }
 
 PropertyDataType ExponentialProperty::d2Value(
@@ -56,16 +56,16 @@ PropertyDataType ExponentialProperty::d2Value(
     ParameterLib::SpatialPosition const& /*pos*/, double const /*t*/,
     double const /*dt*/) const
 {
-    return _exponent_data.type == pv1 && _exponent_data.type == pv2
-               ? std::get<double>(_value) *
+    return exponent_data_.type == pv1 && exponent_data_.type == pv2
+               ? std::get<double>(value_) *
                      boost::math::pow<2>(
-                         std::get<double>(_exponent_data.factor)) *
+                         std::get<double>(exponent_data_.factor)) *
                      std::exp(
-                         -std::get<double>(_exponent_data.factor) *
+                         -std::get<double>(exponent_data_.factor) *
                          (std::get<double>(variable_array[static_cast<int>(
-                              _exponent_data.type)]) -
-                          std::get<double>(_exponent_data.reference_condition)))
-               : decltype(_value){};
+                              exponent_data_.type)]) -
+                          std::get<double>(exponent_data_.reference_condition)))
+               : decltype(value_){};
 }
 
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/ExponentialProperty.h b/MaterialLib/MPL/Properties/ExponentialProperty.h
index 7e8742e6c847fa765b4ea92aa17e3b50671d79db..5a667f30eecd2d393f0973362c936afc1b9bf8cd 100644
--- a/MaterialLib/MPL/Properties/ExponentialProperty.h
+++ b/MaterialLib/MPL/Properties/ExponentialProperty.h
@@ -30,7 +30,7 @@ class ExponentialProperty final : public Property
 {
 public:
     /// This constructor accepts single values of double data type defined in
-    /// the PropertyDataType definition and sets the protected attribute _value
+    /// the PropertyDataType definition and sets the protected attribute value_
     /// of the base class Property to that value.
     ExponentialProperty(PropertyDataType const& property_reference_value,
                         ExponentData const& v);
@@ -55,6 +55,6 @@ public:
                              double const /*dt*/) const override;
 
 private:
-    ExponentData const _exponent_data;
+    ExponentData const exponent_data_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/IdealGasLaw.cpp b/MaterialLib/MPL/Properties/IdealGasLaw.cpp
index 994849681e3cbbe9125524ba5c196b1bcdf20b6a..50f5c46821f99df7e16fc92cd41cd762b985ba37 100644
--- a/MaterialLib/MPL/Properties/IdealGasLaw.cpp
+++ b/MaterialLib/MPL/Properties/IdealGasLaw.cpp
@@ -19,19 +19,19 @@
 
 namespace MaterialPropertyLib
 {
-double molarMass(Phase* _phase, Component* _component,
+double molarMass(Phase* phase_, Component* component_,
                  VariableArray const& variable_array,
                  ParameterLib::SpatialPosition const& pos, double const t,
                  double const dt)
 {
-    if (_phase)  // IdealGasLaw of an entire phase
+    if (phase_)  // IdealGasLaw of an entire phase
     {
-        return _phase->property(PropertyType::molar_mass)
+        return phase_->property(PropertyType::molar_mass)
             .template value<double>(variable_array, pos, t, dt);
     }
-    if (_component)  // IdealGasLaw of a single component
+    if (component_)  // IdealGasLaw of a single component
     {
-        return _component->property(PropertyType::molar_mass)
+        return component_->property(PropertyType::molar_mass)
             .template value<double>(variable_array, pos, t, dt);
     }
     OGS_FATAL(
@@ -51,7 +51,7 @@ PropertyDataType IdealGasLaw::value(VariableArray const& variable_array,
     const double temperature = std::get<double>(
         variable_array[static_cast<int>(Variable::temperature)]);
     double molar_mass =
-        molarMass(_phase, _component, variable_array, pos, t, dt);
+        molarMass(phase_, component_, variable_array, pos, t, dt);
 
     const double density = pressure * molar_mass / gas_constant / temperature;
 
@@ -69,7 +69,7 @@ PropertyDataType IdealGasLaw::dValue(VariableArray const& variable_array,
     const double temperature = std::get<double>(
         variable_array[static_cast<int>(Variable::temperature)]);
     double molar_mass =
-        molarMass(_phase, _component, variable_array, pos, t, dt);
+        molarMass(phase_, component_, variable_array, pos, t, dt);
 
     if (primary_variable == Variable::temperature)
     {
@@ -101,7 +101,7 @@ PropertyDataType IdealGasLaw::d2Value(VariableArray const& variable_array,
     const double temperature = std::get<double>(
         variable_array[static_cast<int>(Variable::temperature)]);
     double molar_mass =
-        molarMass(_phase, _component, variable_array, pos, t, dt);
+        molarMass(phase_, component_, variable_array, pos, t, dt);
 
     if ((primary_variable1 == Variable::phase_pressure) &&
         (primary_variable2 == Variable::phase_pressure))
diff --git a/MaterialLib/MPL/Properties/IdealGasLaw.h b/MaterialLib/MPL/Properties/IdealGasLaw.h
index fcac7b8e9dfec16811957b2277d4fa7453357ff5..1e03291e4f5303860fc827d81d0dbc8168b806c3 100644
--- a/MaterialLib/MPL/Properties/IdealGasLaw.h
+++ b/MaterialLib/MPL/Properties/IdealGasLaw.h
@@ -39,11 +39,11 @@ public:
     {
         if (std::holds_alternative<Phase*>(scale_pointer))
         {
-            _phase = std::get<Phase*>(scale_pointer);
+            phase_ = std::get<Phase*>(scale_pointer);
         }
         else if (std::holds_alternative<Component*>(scale_pointer))
         {
-            _component = std::get<Component*>(scale_pointer);
+            component_ = std::get<Component*>(scale_pointer);
         }
         else
         {
@@ -54,7 +54,7 @@ public:
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& /*pos*/,
                            double const /*t*/,
@@ -70,8 +70,8 @@ public:
                              double const t, double const dt) const override;
 
 private:
-    Phase* _phase = nullptr;
-    Component* _component = nullptr;
+    Phase* phase_ = nullptr;
+    Component* component_ = nullptr;
 };
 
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/LinearProperty.cpp b/MaterialLib/MPL/Properties/LinearProperty.cpp
index 7d250d55e815e84233ca30041068460805ebf9aa..7d5dcb8a9a113dc8921579086d8ec8aa699deff2 100644
--- a/MaterialLib/MPL/Properties/LinearProperty.cpp
+++ b/MaterialLib/MPL/Properties/LinearProperty.cpp
@@ -16,9 +16,9 @@ namespace MaterialPropertyLib
 {
 LinearProperty::LinearProperty(PropertyDataType const& property_reference_value,
                                std::vector<IndependentVariable> const& vs)
-    : _independent_variables(vs)
+    : independent_variables_(vs)
 {
-    _value = property_reference_value;
+    value_ = property_reference_value;
 }
 
 PropertyDataType LinearProperty::value(
@@ -37,12 +37,12 @@ PropertyDataType LinearProperty::value(
     };
 
     double const linearized_ratio_to_reference_value =
-        std::accumulate(_independent_variables.begin(),
-                        _independent_variables.end(),
+        std::accumulate(independent_variables_.begin(),
+                        independent_variables_.end(),
                         1.0,
                         calculate_linearized_ratio);
 
-    return std::get<double>(_value) * linearized_ratio_to_reference_value;
+    return std::get<double>(value_) * linearized_ratio_to_reference_value;
 }
 
 PropertyDataType LinearProperty::dValue(
@@ -51,16 +51,16 @@ PropertyDataType LinearProperty::dValue(
     double const /*dt*/) const
 {
     auto const independent_variable =
-        std::find_if(_independent_variables.begin(),
-                     _independent_variables.end(),
+        std::find_if(independent_variables_.begin(),
+                     independent_variables_.end(),
                      [&primary_variable](auto const& iv) -> bool {
                          return iv.type == primary_variable;
                      });
 
-    return independent_variable != _independent_variables.end()
-               ? std::get<double>(_value) *
+    return independent_variable != independent_variables_.end()
+               ? std::get<double>(value_) *
                      std::get<double>(independent_variable->slope)
-               : decltype(_value){};
+               : decltype(value_){};
 }
 
 PropertyDataType LinearProperty::d2Value(
@@ -68,7 +68,7 @@ PropertyDataType LinearProperty::d2Value(
     Variable const /*pv2*/, ParameterLib::SpatialPosition const& /*pos*/,
     double const /*t*/, double const /*dt*/) const
 {
-    return decltype(_value){};
+    return decltype(value_){};
 }
 
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/LinearProperty.h b/MaterialLib/MPL/Properties/LinearProperty.h
index 697b7e03e21141c423c63b5f60192a9a8316cb62..5f67d214b0a5d722a5e6eeea0e29ade0eae1362d 100644
--- a/MaterialLib/MPL/Properties/LinearProperty.h
+++ b/MaterialLib/MPL/Properties/LinearProperty.h
@@ -28,7 +28,7 @@ class LinearProperty final : public Property
 {
 public:
     /// This constructor accepts single values of double data type defined in
-    /// the PropertyDataType definition and sets the protected attribute _value
+    /// the PropertyDataType definition and sets the protected attribute value_
     /// of the base class Property to that value.
     LinearProperty(PropertyDataType const& property_reference_value,
                    std::vector<IndependentVariable> const& vs);
@@ -57,6 +57,6 @@ public:
                              double const /*dt*/) const override;
 
 private:
-    std::vector<IndependentVariable> const _independent_variables;
+    std::vector<IndependentVariable> const independent_variables_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/ParameterProperty.cpp b/MaterialLib/MPL/Properties/ParameterProperty.cpp
index 6ed3325c5e1b03930ff5bd9655991bc47c57b367..f8b9067d295e5e5c86de58f380d536666eba8e61 100644
--- a/MaterialLib/MPL/Properties/ParameterProperty.cpp
+++ b/MaterialLib/MPL/Properties/ParameterProperty.cpp
@@ -14,7 +14,7 @@ namespace MaterialPropertyLib
 {
 ParameterProperty::ParameterProperty(
     ParameterLib::Parameter<double> const& parameter)
-    : _parameter(parameter)
+    : parameter_(parameter)
 {
 }
 
@@ -23,7 +23,7 @@ PropertyDataType ParameterProperty::value(
     ParameterLib::SpatialPosition const& pos, double const t,
     double const /*dt*/) const
 {
-    return fromVector(_parameter(t, pos));
+    return fromVector(parameter_(t, pos));
 }
 
 PropertyDataType ParameterProperty::dValue(
diff --git a/MaterialLib/MPL/Properties/ParameterProperty.h b/MaterialLib/MPL/Properties/ParameterProperty.h
index 0221de794c102d4dfd133e0fc62016869ebc0827..d7d3480fa1004aa89548ddfa3dfca0c8849f94e2 100644
--- a/MaterialLib/MPL/Properties/ParameterProperty.h
+++ b/MaterialLib/MPL/Properties/ParameterProperty.h
@@ -48,6 +48,6 @@ public:
                              double const /*dt*/) const override;
 
 private:
-    ParameterLib::Parameter<double> const& _parameter;
+    ParameterLib::Parameter<double> const& parameter_;
 };
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.cpp b/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.cpp
index 9d87529f4f59225cf4311e968c399c7af496debb..2433cab622f4194429a54c187acbe9973e636b9e 100644
--- a/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.cpp
+++ b/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.cpp
@@ -25,9 +25,9 @@ PermeabilityOrthotropicPowerLaw<DisplacementDim>::
         std::array<double, DisplacementDim>
             exponents,
         ParameterLib::CoordinateSystem const* const local_coordinate_system)
-    : _k(std::move(intrinsic_permeabilities)),
-      _lambda(std::move(exponents)),
-      _local_coordinate_system(local_coordinate_system)
+    : k_(std::move(intrinsic_permeabilities)),
+      lambda_(std::move(exponents)),
+      local_coordinate_system_(local_coordinate_system)
 {
 }
 
@@ -37,13 +37,13 @@ void PermeabilityOrthotropicPowerLaw<DisplacementDim>::setScale(
 {
     if (std::holds_alternative<Phase*>(scale_pointer))
     {
-        _phase = std::get<Phase*>(scale_pointer);
-        if (_phase->name != "Solid")
+        phase_ = std::get<Phase*>(scale_pointer);
+        if (phase_->name != "Solid")
         {
             OGS_FATAL(
                 "The property 'PermeabilityOrthotropicPowerLaw' must be "
                 "given in the 'Solid' phase, not in '{:s}' phase.",
-                _phase->name);
+                phase_->name);
         }
     }
     else
@@ -65,11 +65,11 @@ PropertyDataType PermeabilityOrthotropicPowerLaw<DisplacementDim>::value(
     // creation/initialization and be stored in a local state.
     // For now assume porosity's initial value does not change with time.
     auto const phi_0 =
-        _phase->hasProperty(PropertyType::transport_porosity)
-            ? _phase->property(PropertyType::transport_porosity)
+        phase_->hasProperty(PropertyType::transport_porosity)
+            ? phase_->property(PropertyType::transport_porosity)
                   .template initialValue<double>(
                       pos, std::numeric_limits<double>::quiet_NaN())
-            : _phase->property(PropertyType::porosity)
+            : phase_->property(PropertyType::porosity)
                   .template initialValue<double>(
                       pos, std::numeric_limits<double>::quiet_NaN());
 
@@ -77,10 +77,10 @@ PropertyDataType PermeabilityOrthotropicPowerLaw<DisplacementDim>::value(
         Eigen::Matrix<double, DisplacementDim, DisplacementDim>::Zero();
 
     Eigen::Matrix<double, DisplacementDim, DisplacementDim> const e =
-        _local_coordinate_system == nullptr
+        local_coordinate_system_ == nullptr
             ? Eigen::Matrix<double, DisplacementDim,
                             DisplacementDim>::Identity()
-            : _local_coordinate_system->transformation<DisplacementDim>(pos);
+            : local_coordinate_system_->transformation<DisplacementDim>(pos);
 
     // k = \sum_i k_i (\phi / \phi_0)^{\lambda_i} e_i \otimes e_i
     // e_i \otimes e_i = square matrix e_i,0^2 e_i,0*e_i,1 etc.
@@ -89,7 +89,7 @@ PropertyDataType PermeabilityOrthotropicPowerLaw<DisplacementDim>::value(
         Eigen::Matrix<double, DisplacementDim, DisplacementDim> const
             ei_otimes_ei = e.col(i) * e.col(i).transpose();
 
-        k += _k[i] * std::pow(phi / phi_0, _lambda[i]) * ei_otimes_ei;
+        k += k_[i] * std::pow(phi / phi_0, lambda_[i]) * ei_otimes_ei;
     }
     return k;
 }
diff --git a/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.h b/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.h
index 175a4c873e51ea274e869da2e0a058f018f72b47..f744d17e06d287ecdc2b7ba018f93cb3e3199815 100644
--- a/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.h
+++ b/MaterialLib/MPL/Properties/PermeabilityOrthotropicPowerLaw.h
@@ -35,12 +35,12 @@ template <int DisplacementDim>
 class PermeabilityOrthotropicPowerLaw final : public Property
 {
 private:
-    Phase* _phase = nullptr;
+    Phase* phase_ = nullptr;
     /// Intrinsic permeabilities, one for each spatial dimension.
-    std::array<double, DisplacementDim> const _k;
+    std::array<double, DisplacementDim> const k_;
     /// Exponents, one for each spatial dimension.
-    std::array<double, DisplacementDim> const _lambda;
-    ParameterLib::CoordinateSystem const* const _local_coordinate_system;
+    std::array<double, DisplacementDim> const lambda_;
+    ParameterLib::CoordinateSystem const* const local_coordinate_system_;
 
 public:
     PermeabilityOrthotropicPowerLaw(
diff --git a/MaterialLib/MPL/Properties/PorosityFromMassBalance.cpp b/MaterialLib/MPL/Properties/PorosityFromMassBalance.cpp
index 552683140c4633ecbf1e7a4ae2ba0f375b79176b..d28e8e1c21a22babb74363c3c4825786a3232e20 100644
--- a/MaterialLib/MPL/Properties/PorosityFromMassBalance.cpp
+++ b/MaterialLib/MPL/Properties/PorosityFromMassBalance.cpp
@@ -21,13 +21,13 @@ void PorosityFromMassBalance::setScale(
 {
     if (std::holds_alternative<Phase*>(scale_pointer))
     {
-        _phase = std::get<Phase*>(scale_pointer);
-        if (_phase->name != "Solid")
+        phase_ = std::get<Phase*>(scale_pointer);
+        if (phase_->name != "Solid")
         {
             OGS_FATAL(
                 "The property 'PorosityFromMassBalance' must be "
                 "given in the 'Solid' phase, not in '{:s}' phase.",
-                _phase->name);
+                phase_->name);
         }
     }
     else
@@ -43,10 +43,10 @@ PropertyDataType PorosityFromMassBalance::value(
     ParameterLib::SpatialPosition const& pos,
     double const t, double const dt) const
 {
-    double const K_SR = _phase->property(PropertyType::bulk_modulus)
+    double const K_SR = phase_->property(PropertyType::bulk_modulus)
                             .template value<double>(variable_array, pos, t, dt);
     auto const alpha_b =
-        _phase->property(PropertyType::biot_coefficient)
+        phase_->property(PropertyType::biot_coefficient)
             .template value<double>(variable_array, pos, t, dt);
 
     double const e_dot = std::get<double>(
@@ -59,7 +59,7 @@ PropertyDataType PorosityFromMassBalance::value(
         variable_array[static_cast<int>(Variable::porosity)]);
 
     double const w = dt * (e_dot + p_eff_dot / K_SR);
-    return std::clamp((phi + alpha_b * w) / (1 + w), _phi_min, _phi_max);
+    return std::clamp((phi + alpha_b * w) / (1 + w), phi_min_, phi_max_);
 }
 
 PropertyDataType PorosityFromMassBalance::dValue(
diff --git a/MaterialLib/MPL/Properties/PorosityFromMassBalance.h b/MaterialLib/MPL/Properties/PorosityFromMassBalance.h
index 7ca7a9e52db4513a980498119817a9e4586e4fbf..0b5e31f26c246d5083df524f08a4f22f43ac90e3 100644
--- a/MaterialLib/MPL/Properties/PorosityFromMassBalance.h
+++ b/MaterialLib/MPL/Properties/PorosityFromMassBalance.h
@@ -25,18 +25,18 @@ class Component;
 class PorosityFromMassBalance final : public Property
 {
 private:
-    Phase* _phase = nullptr;
+    Phase* phase_ = nullptr;
 
     /// Parameter, which is used by FEM to set the initial porosity value.
-    ParameterLib::Parameter<double> const& _phi0;
-    double const _phi_min;  //< Lower limit for the porosity.
-    double const _phi_max;  //< Upper limit for the porosity.
+    ParameterLib::Parameter<double> const& phi0_;
+    double const phi_min_;  //< Lower limit for the porosity.
+    double const phi_max_;  //< Upper limit for the porosity.
 
 public:
     PorosityFromMassBalance(
         ParameterLib::Parameter<double> const& initial_porosity,
         double const phi_min, double const phi_max)
-        : _phi0(initial_porosity), _phi_min(phi_min), _phi_max(phi_max)
+        : phi0_(initial_porosity), phi_min_(phi_min), phi_max_(phi_max)
     {
     }
 
@@ -46,7 +46,7 @@ public:
     PropertyDataType initialValue(ParameterLib::SpatialPosition const& pos,
                                   double const t) const override
     {
-        return fromVector(_phi0(t, pos));
+        return fromVector(phi0_(t, pos));
     }
 
     PropertyDataType value(VariableArray const& variable_array,
diff --git a/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.cpp b/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.cpp
index eca986d0748ec80af4919e76b9e582379561a71a..d2213c3d83bee2b842b8a5a5c34f477612ef6f15 100644
--- a/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.cpp
+++ b/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.cpp
@@ -27,11 +27,11 @@ RelPermBrooksCorey::RelPermBrooksCorey(
     const double min_relative_permeability_liquid,
     const double min_relative_permeability_gas,
     const double exponent)
-    : _residual_liquid_saturation(residual_liquid_saturation),
-      _residual_gas_saturation(residual_gas_saturation),
-      _min_relative_permeability_liquid(min_relative_permeability_liquid),
-      _min_relative_permeability_gas(min_relative_permeability_gas),
-      _exponent(exponent){};
+    : residual_liquid_saturation_(residual_liquid_saturation),
+      residual_gas_saturation_(residual_gas_saturation),
+      min_relative_permeability_liquid_(min_relative_permeability_liquid),
+      min_relative_permeability_gas_(min_relative_permeability_gas),
+      exponent_(exponent){};
 
 PropertyDataType RelPermBrooksCorey::value(
     VariableArray const& variable_array,
@@ -42,15 +42,15 @@ PropertyDataType RelPermBrooksCorey::value(
     /// correct value. In order to speed up the computing time, saturation could
     /// be insertred into the primary variable array after it is computed in the
     /// FEM assembly.
-    auto const s_L = _medium->property(PropertyType::saturation)
+    auto const s_L = medium_->property(PropertyType::saturation)
                          .template value<double>(variable_array, pos, t, dt);
 
-    auto const s_L_res = _residual_liquid_saturation;
-    auto const s_L_max = 1. - _residual_gas_saturation;
-    auto const k_rel_min_LR = _min_relative_permeability_liquid;
-    auto const k_rel_min_GR = _min_relative_permeability_gas;
+    auto const s_L_res = residual_liquid_saturation_;
+    auto const s_L_max = 1. - residual_gas_saturation_;
+    auto const k_rel_min_LR = min_relative_permeability_liquid_;
+    auto const k_rel_min_GR = min_relative_permeability_gas_;
 
-    auto const lambda = _exponent;
+    auto const lambda = exponent_;
 
     auto const s_eff = (s_L - s_L_res) / (s_L_max - s_L_res);
 
@@ -81,12 +81,12 @@ PropertyDataType RelPermBrooksCorey::dValue(
     assert((primary_variable == Variable::liquid_saturation) &&
            "RelPermBrooksCorey::dValue is implemented for "
            " derivatives with respect to liquid saturation only.");
-    auto const s_L = _medium->property(PropertyType::saturation)
+    auto const s_L = medium_->property(PropertyType::saturation)
                          .template value<double>(variable_array, pos, t, dt);
 
-    auto const s_L_res = _residual_liquid_saturation;
-    auto const s_L_max = 1. - _residual_gas_saturation;
-    auto const lambda = _exponent;
+    auto const s_L_res = residual_liquid_saturation_;
+    auto const s_L_max = 1. - residual_gas_saturation_;
+    auto const lambda = exponent_;
 
     auto const s_eff = (s_L - s_L_res) / (s_L_max - s_L_res);
     if ((s_eff < 0.) || (s_eff > 1.))
@@ -98,10 +98,10 @@ PropertyDataType RelPermBrooksCorey::dValue(
 
     auto const dk_rel_LRdsL = dk_rel_LRdse * d_se_d_sL;
 
-    auto const _2L_L = (2. + lambda) / lambda;
+    auto const twoL_L = (2. + lambda) / lambda;
     auto const dk_rel_GRdse =
-        -2. * (1 - s_eff) * (1. - std::pow(s_eff, _2L_L)) -
-        _2L_L * std::pow(s_eff, _2L_L - 1.) * (1. - s_eff) * (1. - s_eff);
+        -2. * (1 - s_eff) * (1. - std::pow(s_eff, twoL_L)) -
+        twoL_L * std::pow(s_eff, twoL_L - 1.) * (1. - s_eff) * (1. - s_eff);
 
     auto const dk_rel_GRdsL = dk_rel_GRdse * d_se_d_sL;
     return Eigen::Vector2d{dk_rel_LRdsL, dk_rel_GRdsL};
diff --git a/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.h b/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.h
index a2f354723d9dcdc16caa62dea1fb2baa90719a03..000d67eea06430aa34feb478c2997ea8b591104d 100644
--- a/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.h
+++ b/MaterialLib/MPL/Properties/RelativePermeability/RelPermBrooksCorey.h
@@ -31,18 +31,18 @@ class Component;
 class RelPermBrooksCorey final : public Property
 {
 private:
-    Medium* _medium = nullptr;
-    const double _residual_liquid_saturation;
-    const double _residual_gas_saturation;
-    const double _min_relative_permeability_liquid;
-    const double _min_relative_permeability_gas;
-    const double _exponent;
+    Medium* medium_ = nullptr;
+    const double residual_liquid_saturation_;
+    const double residual_gas_saturation_;
+    const double min_relative_permeability_liquid_;
+    const double min_relative_permeability_gas_;
+    const double exponent_;
 
 public:
     RelPermBrooksCorey(const double /*residual_liquid_saturation*/,
                        const double /*residual_gas_saturation*/,
-                       const double /*_min_relative_permeability_liquid*/,
-                       const double /*_min_relative_permeability_gas*/,
+                       const double /*min_relative_permeability_liquid_*/,
+                       const double /*min_relative_permeability_gas_*/,
                        const double /*exponent*/
     );
     /// This method assigns a pointer to the material object that is the owner
@@ -52,7 +52,7 @@ public:
     {
         if (std::holds_alternative<Medium*>(scale_pointer))
         {
-            _medium = std::get<Medium*>(scale_pointer);
+            medium_ = std::get<Medium*>(scale_pointer);
         }
         else
         {
@@ -63,7 +63,7 @@ public:
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& pos,
                            double const t, double const dt) const override;
diff --git a/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.cpp b/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.cpp
index 359524a25da7188c2cb8698f4ddfe4c01c94a4a5..9ca4f750242d09aae983fff555d6bfa5ff6bc7aa 100644
--- a/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.cpp
+++ b/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.cpp
@@ -31,10 +31,10 @@ PropertyDataType RelPermLiakopoulos::value(
     /// correct value. In order to speed up the computing time, saturation could
     /// be insertred into the primary variable array after it is computed in the
     /// FEM assembly.
-    auto const s_L = _medium->property(PropertyType::saturation)
+    auto const s_L = medium_->property(PropertyType::saturation)
                          .template value<double>(variable_array, pos, t, dt);
-    auto const s_L_res = _residual_liquid_saturation;
-    auto const k_rel_min_GR = _min_relative_permeability_gas;
+    auto const s_L_res = residual_liquid_saturation_;
+    auto const k_rel_min_GR = min_relative_permeability_gas_;
 
     if (s_L <= s_L_res)
     {
@@ -46,9 +46,9 @@ PropertyDataType RelPermLiakopoulos::value(
         return Eigen::Vector2d{1., k_rel_min_GR};
     }
 
-    auto const a = _parameter_a;
-    auto const b = _parameter_b;
-    auto const lambda = _exponent;
+    auto const a = parameter_a_;
+    auto const b = parameter_b_;
+    auto const lambda = exponent_;
 
     auto const s_eff = (s_L - s_L_res) / (1. - s_L_res);
 
@@ -69,27 +69,27 @@ PropertyDataType RelPermLiakopoulos::dValue(
     assert((primary_variable == Variable::liquid_saturation) &&
            "RelPermLiakopoulos::dValue is implemented for "
            " derivatives with respect to liquid saturation only.");
-    auto const s_L = _medium->property(PropertyType::saturation)
+    auto const s_L = medium_->property(PropertyType::saturation)
                          .template value<double>(variable_array, pos, t, dt);
-    auto const s_L_res = _residual_liquid_saturation;
-    auto const s_L_max = _maximal_liquid_saturation;
+    auto const s_L_res = residual_liquid_saturation_;
+    auto const s_L_max = maximal_liquid_saturation_;
 
     const double s_L_within_range = std::min(std::max(s_L_res, s_L), s_L_max);
 
-    auto const lambda = _exponent;
-    auto const a = _parameter_a;
-    auto const b = _parameter_b;
+    auto const lambda = exponent_;
+    auto const a = parameter_a_;
+    auto const b = parameter_b_;
 
     auto const s_eff = (s_L_within_range - s_L_res) / (s_L_max - s_L_res);
 
     auto const dk_rel_LRdsL = a * b * std::pow(1. - s_L_within_range, b - 1.);
 
-    auto const _2L_L = (2. + lambda) / lambda;
+    auto const twoL_L = (2. + lambda) / lambda;
     auto const s_G_eff = 1. - s_eff;
     auto const dk_rel_GRdse =
-        -2. * s_G_eff * (1. - std::pow(s_eff, _2L_L)) -
-        _2L_L * std::pow(s_eff, _2L_L - 1.) * s_G_eff * s_G_eff;
-    auto const dk_rel_GRdsL = dk_rel_GRdse * _dse_dsL;
+        -2. * s_G_eff * (1. - std::pow(s_eff, twoL_L)) -
+        twoL_L * std::pow(s_eff, twoL_L - 1.) * s_G_eff * s_G_eff;
+    auto const dk_rel_GRdsL = dk_rel_GRdse * dse_dsL_;
 
     return Eigen::Vector2d{dk_rel_LRdsL, dk_rel_GRdsL};
 }
diff --git a/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.h b/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.h
index 728ab6afb296382ca8cb64bb3d9e7a0983930c60..0014e3248bdc15daf3c6fd7dba7168e68cc43280 100644
--- a/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.h
+++ b/MaterialLib/MPL/Properties/RelativePermeability/RelPermLiakopoulos.h
@@ -47,7 +47,7 @@ s^{\mathrm{r}}_{\mathrm{L}}}\f]
 class RelPermLiakopoulos final : public Property
 {
 private:
-    Medium* _medium = nullptr;
+    Medium* medium_ = nullptr;
     /**
     Parameters for Liakopoulos relative permeability:
     Asadi, R., Ataie-Ashtiani, B. (2015): A Comparison of finite volume
@@ -57,14 +57,14 @@ private:
     Those parameters are fixed for that particular model, no need to change
     them.
     */
-    const double _residual_liquid_saturation = 0.2;
-    const double _maximal_liquid_saturation = 1.;
-    const double _parameter_a = 2.207;
-    const double _parameter_b = 1.0121;
-    const double _exponent = 3.;
-    const double _min_relative_permeability_gas = 1.0e-4;
-    const double _dse_dsL =
-        1. / (_maximal_liquid_saturation - _residual_liquid_saturation);
+    const double residual_liquid_saturation_ = 0.2;
+    const double maximal_liquid_saturation_ = 1.;
+    const double parameter_a_ = 2.207;
+    const double parameter_b_ = 1.0121;
+    const double exponent_ = 3.;
+    const double min_relative_permeability_gas_ = 1.0e-4;
+    const double dse_dsL_ =
+        1. / (maximal_liquid_saturation_ - residual_liquid_saturation_);
 
 public:
     /// This method assigns a pointer to the meterial object that is the owner
@@ -74,7 +74,7 @@ public:
     {
         if (std::holds_alternative<Medium*>(scale_pointer))
         {
-            _medium = std::get<Medium*>(scale_pointer);
+            medium_ = std::get<Medium*>(scale_pointer);
         }
         else
         {
@@ -85,7 +85,7 @@ public:
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& pos,
                            double const t, double const dt) const override;
diff --git a/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.cpp b/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.cpp
index 7cc97329c940c8737a4d33a2cd7ea5050ff19478..cff4bd5493b092f2b93da99e366f3815707cd3f0 100644
--- a/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.cpp
+++ b/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.cpp
@@ -22,17 +22,17 @@ RelPermVanGenuchten::RelPermVanGenuchten(
     double const residual_gas_saturation,
     double const min_relative_permeability_liquid,
     double const exponent)
-    : _S_L_res(residual_liquid_saturation),
-      _S_L_max(1. - residual_gas_saturation),
-      _k_rel_min(min_relative_permeability_liquid),
-      _m(exponent)
+    : S_L_res_(residual_liquid_saturation),
+      S_L_max_(1. - residual_gas_saturation),
+      k_rel_min_(min_relative_permeability_liquid),
+      m_(exponent)
 {
-    if (!(_m > 0 && _m < 1))
+    if (!(m_ > 0 && m_ < 1))
     {
         OGS_FATAL(
             "The exponent value m = {:g} of van Genuchten relative "
             "permeability model, is out of its range of (0, 1)",
-            _m);
+            m_);
     }
 }
 
@@ -44,12 +44,12 @@ PropertyDataType RelPermVanGenuchten::value(
     double const S_L = std::clamp(
         std::get<double>(
             variable_array[static_cast<int>(Variable::liquid_saturation)]),
-        _S_L_res, _S_L_max);
+        S_L_res_, S_L_max_);
 
-    double const S_eff = (S_L - _S_L_res) / (_S_L_max - _S_L_res);
-    double const v = 1. - std::pow(1. - std::pow(S_eff, 1. / _m), _m);
+    double const S_eff = (S_L - S_L_res_) / (S_L_max_ - S_L_res_);
+    double const v = 1. - std::pow(1. - std::pow(S_eff, 1. / m_), m_);
     double const k_rel = std::sqrt(S_eff) * v * v;
-    return std::max(_k_rel_min, k_rel);
+    return std::max(k_rel_min_, k_rel);
 }
 
 PropertyDataType RelPermVanGenuchten::dValue(
@@ -64,9 +64,9 @@ PropertyDataType RelPermVanGenuchten::dValue(
     double const S_L = std::clamp(
         std::get<double>(
             variable_array[static_cast<int>(Variable::liquid_saturation)]),
-        _S_L_res, _S_L_max);
+        S_L_res_, S_L_max_);
 
-    double const S_eff = (S_L - _S_L_res) / (_S_L_max - _S_L_res);
+    double const S_eff = (S_L - S_L_res_) / (S_L_max_ - S_L_res_);
     if (S_eff <= 0)  // prevent division by zero
     {
         return 0;
@@ -77,20 +77,20 @@ PropertyDataType RelPermVanGenuchten::dValue(
         return 0;
     }
 
-    double const S_eff_to_1_over_m = std::pow(S_eff, 1. / _m);
-    double const v = 1. - std::pow(1. - S_eff_to_1_over_m, _m);
+    double const S_eff_to_1_over_m = std::pow(S_eff, 1. / m_);
+    double const v = 1. - std::pow(1. - S_eff_to_1_over_m, m_);
     double const sqrt_S_eff = std::sqrt(S_eff);
     double const k_rel = sqrt_S_eff * v * v;
 
-    if (k_rel < _k_rel_min)
+    if (k_rel < k_rel_min_)
     {
         return 0;
     }
 
     return (0.5 * v * v / sqrt_S_eff +
-            2. * sqrt_S_eff * v * std::pow(1. - S_eff_to_1_over_m, _m - 1.) *
+            2. * sqrt_S_eff * v * std::pow(1. - S_eff_to_1_over_m, m_ - 1.) *
                 S_eff_to_1_over_m / S_eff) /
-           (_S_L_max - _S_L_res);
+           (S_L_max_ - S_L_res_);
 }
 
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.h b/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.h
index e664269fc47992e77c3002f0ee1681fb3b54ba98..83bed381cf0cde1c61d0602a2167278b5292d073 100644
--- a/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.h
+++ b/MaterialLib/MPL/Properties/RelativePermeability/RelPermVanGenuchten.h
@@ -25,11 +25,11 @@ class Component;
 class RelPermVanGenuchten final : public Property
 {
 private:
-    double const _S_L_res;
-    double const _S_L_max;
-    double const _k_rel_min;
-    double const _m;
-    Medium* _medium = nullptr;
+    double const S_L_res_;
+    double const S_L_max_;
+    double const k_rel_min_;
+    double const m_;
+    Medium* medium_ = nullptr;
 
 public:
     RelPermVanGenuchten(double const residual_liquid_saturation,
@@ -43,7 +43,7 @@ public:
     {
         if (std::holds_alternative<Medium*>(scale_pointer))
         {
-            _medium = std::get<Medium*>(scale_pointer);
+            medium_ = std::get<Medium*>(scale_pointer);
         }
         else
         {
@@ -54,7 +54,7 @@ public:
     }
 
     /// Those methods override the base class implementations and
-    /// actually compute and set the property _values and _dValues.
+    /// actually compute and set the property values_ and dValues_.
     PropertyDataType value(VariableArray const& variable_array,
                            ParameterLib::SpatialPosition const& pos,
                            double const t, double const dt) const override;
diff --git a/MaterialLib/MPL/Properties/SaturationDependentSwelling.cpp b/MaterialLib/MPL/Properties/SaturationDependentSwelling.cpp
index 5f7eb5802724bf774ac289c6a2f3e49fafe2f0c5..d70f3bc99d81d15bf307d6872256a3423fb705e9 100644
--- a/MaterialLib/MPL/Properties/SaturationDependentSwelling.cpp
+++ b/MaterialLib/MPL/Properties/SaturationDependentSwelling.cpp
@@ -24,11 +24,11 @@ SaturationDependentSwelling::SaturationDependentSwelling(
     double const lower_saturation_limit,
     double const upper_saturation_limit,
     ParameterLib::CoordinateSystem const* const local_coordinate_system)
-    : _p(std::move(swelling_pressures)),
-      _lambda(std::move(exponents)),
-      _S_min(lower_saturation_limit),
-      _S_max(upper_saturation_limit),
-      _local_coordinate_system(local_coordinate_system)
+    : p_(std::move(swelling_pressures)),
+      lambda_(std::move(exponents)),
+      S_min_(lower_saturation_limit),
+      S_max_(upper_saturation_limit),
+      local_coordinate_system_(local_coordinate_system)
 {
 }
 
@@ -37,13 +37,13 @@ void SaturationDependentSwelling::setScale(
 {
     if (std::holds_alternative<Phase*>(scale_pointer))
     {
-        _phase = std::get<Phase*>(scale_pointer);
-        if (_phase->name != "Solid")
+        phase_ = std::get<Phase*>(scale_pointer);
+        if (phase_->name != "Solid")
         {
             OGS_FATAL(
                 "The property 'SaturationDependentSwelling' must be "
                 "given in the 'Solid' phase, not in '{:s}' phase.",
-                _phase->name);
+                phase_->name);
         }
     }
     else
@@ -65,23 +65,23 @@ PropertyDataType SaturationDependentSwelling::value(
         variable_array[static_cast<int>(Variable::liquid_saturation_rate)]);
 
     Eigen::Matrix<double, 3, 3> const e =
-        _local_coordinate_system == nullptr
+        local_coordinate_system_ == nullptr
             ? Eigen::Matrix<double, 3, 3>::Identity()
-            : _local_coordinate_system->transformation_3d(pos);
+            : local_coordinate_system_->transformation_3d(pos);
 
     Eigen::Matrix<double, 3, 3> delta_sigma_sw =
         Eigen::Matrix<double, 3, 3>::Zero();
 
-    if (S_L < _S_min)
+    if (S_L < S_min_)
     {
         return delta_sigma_sw;   // still being zero.
     }
 
     double const S_L_prev = S_L - S_L_dot * dt;
 
-    double const S_eff = std::clamp((S_L - _S_min) / (_S_max - _S_min), 0., 1.);
+    double const S_eff = std::clamp((S_L - S_min_) / (S_max_ - S_min_), 0., 1.);
     double const S_eff_prev =
-        std::clamp((S_L_prev - _S_min) / (_S_max - _S_min), 0., 1.);
+        std::clamp((S_L_prev - S_min_) / (S_max_ - S_min_), 0., 1.);
 
     double const delta_S_eff = S_eff - S_eff_prev;
 
@@ -94,7 +94,7 @@ PropertyDataType SaturationDependentSwelling::value(
             e.col(i) * e.col(i).transpose();
 
         delta_sigma_sw -=
-            _lambda[i] * _p[i] * std::pow(S_eff, _lambda[i] - 1) * ei_otimes_ei;
+            lambda_[i] * p_[i] * std::pow(S_eff, lambda_[i] - 1) * ei_otimes_ei;
     }
 
     return (delta_sigma_sw * delta_S_eff / dt).eval();
@@ -116,23 +116,23 @@ PropertyDataType SaturationDependentSwelling::dValue(
         variable_array[static_cast<int>(Variable::liquid_saturation_rate)]);
 
     Eigen::Matrix<double, 3, 3> const e =
-        _local_coordinate_system == nullptr
+        local_coordinate_system_ == nullptr
             ? Eigen::Matrix<double, 3, 3>::Identity()
-            : _local_coordinate_system->transformation_3d(pos);
+            : local_coordinate_system_->transformation_3d(pos);
 
     Eigen::Matrix<double, 3, 3> delta_sigma_sw =
         Eigen::Matrix<double, 3, 3>::Zero();
 
-    if (S_L < _S_min)
+    if (S_L < S_min_)
     {
         return delta_sigma_sw;   // still being zero.
     }
 
     double const S_L_prev = S_L - S_L_dot * dt;
 
-    double const S_eff = std::clamp((S_L - _S_min) / (_S_max - _S_min), 0., 1.);
+    double const S_eff = std::clamp((S_L - S_min_) / (S_max_ - S_min_), 0., 1.);
     double const S_eff_prev =
-        std::clamp((S_L_prev - _S_min) / (_S_max - _S_min), 0., 1.);
+        std::clamp((S_L_prev - S_min_) / (S_max_ - S_min_), 0., 1.);
 
     double const delta_S_eff = S_eff - S_eff_prev;
 
@@ -148,8 +148,8 @@ PropertyDataType SaturationDependentSwelling::dValue(
             e.col(i) * e.col(i).transpose();
 
         delta_sigma_sw +=
-            _lambda[i] * _p[i] * std::pow(S_eff, _lambda[i] - 1) * ei_otimes_ei;
+            lambda_[i] * p_[i] * std::pow(S_eff, lambda_[i] - 1) * ei_otimes_ei;
     }
-    return (delta_sigma_sw / (_S_max - _S_min)).eval();
+    return (delta_sigma_sw / (S_max_ - S_min_)).eval();
 }
 }  // namespace MaterialPropertyLib
diff --git a/MaterialLib/MPL/Properties/SaturationDependentSwelling.h b/MaterialLib/MPL/Properties/SaturationDependentSwelling.h
index ce76ed5bc20b0aa163d0c90283a691b74af5d073..5ef334d7f54de8890062ba0402ccf16c61051625 100644
--- a/MaterialLib/MPL/Properties/SaturationDependentSwelling.h
+++ b/MaterialLib/MPL/Properties/SaturationDependentSwelling.h
@@ -34,14 +34,14 @@ class Component;
 class SaturationDependentSwelling final : public Property
 {
 private:
-    Phase* _phase = nullptr;
+    Phase* phase_ = nullptr;
     /// Maximum swelling pressures, one for each spatial dimension.
-    std::array<double, 3> const _p;
+    std::array<double, 3> const p_;
     /// Exponents, one for each spatial dimension.
-    std::array<double, 3> const _lambda;
-    double const _S_min;  //< Lower saturation limit.
-    double const _S_max;  //< Upper saturation limit.
-    ParameterLib::CoordinateSystem const* const _local_coordinate_system;
+    std::array<double, 3> const lambda_;
+    double const S_min_;  //< Lower saturation limit.
+    double const S_max_;  //< Upper saturation limit.
+    ParameterLib::CoordinateSystem const* const local_coordinate_system_;
 
 public:
     SaturationDependentSwelling(
diff --git a/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.cpp b/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.cpp
index 8d5459dccc33f1c31d9486cbb35bed02229f675c..4d13a4b2d50ebfc1c6caf8b77085bacf8b4466d1 100644
--- a/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.cpp
+++ b/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.cpp
@@ -21,13 +21,13 @@ void TransportPorosityFromMassBalance::setScale(
 {
     if (std::holds_alternative<Phase*>(scale_pointer))
     {
-        _phase = std::get<Phase*>(scale_pointer);
-        if (_phase->name != "Solid")
+        phase_ = std::get<Phase*>(scale_pointer);
+        if (phase_->name != "Solid")
         {
             OGS_FATAL(
                 "The property 'TransportPorosityFromMassBalance' must be "
                 "given in the 'Solid' phase, not in '{:s}' phase.",
-                _phase->name);
+                phase_->name);
         }
     }
     else
@@ -43,10 +43,10 @@ PropertyDataType TransportPorosityFromMassBalance::value(
     ParameterLib::SpatialPosition const& pos, double const t,
     double const dt) const
 {
-    double const K_SR = _phase->property(PropertyType::bulk_modulus)
+    double const K_SR = phase_->property(PropertyType::bulk_modulus)
                             .template value<double>(variable_array, pos, t, dt);
     auto const alpha_b =
-        _phase->property(PropertyType::biot_coefficient)
+        phase_->property(PropertyType::biot_coefficient)
             .template value<double>(variable_array, pos, t, dt);
 
     double const e_dot = std::get<double>(
@@ -62,7 +62,7 @@ PropertyDataType TransportPorosityFromMassBalance::value(
         variable_array[static_cast<int>(Variable::transport_porosity)]);
 
     double const w = dt * (e_dot + p_eff_dot / K_SR);
-    return std::clamp(phi_tr_prev + (alpha_b - phi) * w, _phi_min, _phi_max);
+    return std::clamp(phi_tr_prev + (alpha_b - phi) * w, phi_min_, phi_max_);
 }
 
 PropertyDataType TransportPorosityFromMassBalance::dValue(
diff --git a/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.h b/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.h
index cff11173ad98974cae09c64b95ab3db7cc65e3b0..cf2794d68eb95aaafb492024fae3993707f2c199 100644
--- a/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.h
+++ b/MaterialLib/MPL/Properties/TransportPorosityFromMassBalance.h
@@ -24,18 +24,18 @@ class Component;
 class TransportPorosityFromMassBalance final : public Property
 {
 private:
-    Phase* _phase = nullptr;
+    Phase* phase_ = nullptr;
 
     /// Parameter, which is used by FEM to set the initial porosity value.
-    ParameterLib::Parameter<double> const& _phi0;
-    double const _phi_min;  //< Lower limit for the porosity.
-    double const _phi_max;  //< Upper limit for the porosity.
+    ParameterLib::Parameter<double> const& phi0_;
+    double const phi_min_;  //< Lower limit for the porosity.
+    double const phi_max_;  //< Upper limit for the porosity.
 
 public:
     TransportPorosityFromMassBalance(
         ParameterLib::Parameter<double> const& initial_porosity,
         double const phi_min, double const phi_max)
-        : _phi0(initial_porosity), _phi_min(phi_min), _phi_max(phi_max)
+        : phi0_(initial_porosity), phi_min_(phi_min), phi_max_(phi_max)
     {
     }
 
@@ -45,7 +45,7 @@ public:
     PropertyDataType initialValue(ParameterLib::SpatialPosition const& pos,
                                   double const t) const override
     {
-        return fromVector(_phi0(t, pos));
+        return fromVector(phi0_(t, pos));
     }
 
     PropertyDataType value(VariableArray const& variable_array,
diff --git a/MaterialLib/MPL/Property.cpp b/MaterialLib/MPL/Property.cpp
index 829814d516f89b3ecd8a013cebd40b061cfe6a1e..2754e8e2f39fa1dc8cb5432e39faa2bf37d8a3d1 100644
--- a/MaterialLib/MPL/Property.cpp
+++ b/MaterialLib/MPL/Property.cpp
@@ -67,7 +67,7 @@ PropertyDataType Property::initialValue(
 
 PropertyDataType Property::value() const
 {
-    return _value;
+    return value_;
 }
 
 /// The default implementation of this method only returns the property value
@@ -76,7 +76,7 @@ PropertyDataType Property::value(VariableArray const& /*variable_array*/,
                                  ParameterLib::SpatialPosition const& /*pos*/,
                                  double const /*t*/, double const /*dt*/) const
 {
-    return _value;
+    return value_;
 }
 
 /// The default implementation of this method only returns the
@@ -86,7 +86,7 @@ PropertyDataType Property::dValue(VariableArray const& /*variable_array*/,
                                   ParameterLib::SpatialPosition const& /*pos*/,
                                   double const /*t*/, double const /*dt*/) const
 {
-    return _dvalue;
+    return dvalue_;
 }
 
 /// Default implementation: 2nd derivative of any constant property is zero.
diff --git a/MaterialLib/MPL/Property.h b/MaterialLib/MPL/Property.h
index c7ce1f8a00c7b965076a9094c9d61b2cf6fa7870..847aaabec410545d146094ec299d032fadddba7b 100644
--- a/MaterialLib/MPL/Property.h
+++ b/MaterialLib/MPL/Property.h
@@ -50,7 +50,7 @@ public:
     virtual PropertyDataType initialValue(
         ParameterLib::SpatialPosition const& pos, double const t) const;
 
-    /// This virtual method simply returns the private _value attribute without
+    /// This virtual method simply returns the private value_ attribute without
     /// changing it.
     virtual PropertyDataType value() const;
     /// This virtual method will compute the property value based on the primary
@@ -114,8 +114,8 @@ public:
 
 protected:
     /// The single value of a property.
-    PropertyDataType _value;
-    PropertyDataType _dvalue;
+    PropertyDataType value_;
+    PropertyDataType dvalue_;
 };
 
 inline void overwriteExistingProperties(