[Web] Added a description of "A test with nodal source term"

web/content/docs/benchmarks/hydro-mechanics/nodal_source_test.md

++++
+title = "A test with nodal source term"
+date = 2021-04-14T15:31:38+02:00
+weight = 151
+project = "HydroMechanics/HydroMechanics/NodalSourceTerm/nodal_source_test.prj"
+author = "Wenqing Wang"
+
+[menu]
+  [menu.benchmarks]
+    parent = "hydro-mechanics"
+
++++
+
+{{< data-link >}}
+
+---
+
+The purpose of this benchmark is to test the source term type of NodalSourceTerm
+ being applied to the hydraulic equation in the computations with the
+ Taylor-Hood elements,
+ e.g., the pressure interpolation using linear shape function,
+ and the displacement interpolation using quadratic shape function.
+
+The problem is solved on a rectangular domain 2 m $\times$ 1 m.
+Nodal fluid flux is applied on the left boundary nodes with a value of
+ 0.001 kg/s via the property of NodalSourceTerm.
+ The pore pressure on the right boundary is equal to the initial pore pressure
+  of $10^5$ Pa.
+ The displacement in the normal direction of all boundaries except
+the left one is fixed.
+
+Fluid and solid are incompressible.
+
+All involved parameters are listed in the following tables:
+<table>
+<caption>Material Properties</caption>
+<thead>
+<tr class="header">
+<th align="left">Property</th>
+<th align="left">Value</th>
+<th align="left">Unit</th>
+</tr>
+</thead>
+<tbody>
+<tr class="odd">
+<td align="left">Fluid density</td>
+<td align="left">$10^3$</td>
+<td align="left">kg/m$^3$</td>
+</tr>
+<tr class="odd">
+<td align="left">Viscosity</td>
+<td align="left">$10^{-3}$</td>
+<td align="left">Pa$\cdot$s</td>
+</tr>
+<tr class="odd">
+<td align="left">Permeability</td>
+<td align="left">$10^{-14}$</td>
+<td align="left">m$^2$</td>
+</tr>
+<tr class="even">
+<td align="left">Young’s modulus (bulk)</td>
+<td align="left">$2.5\cdot 10^9$</td>
+<td align="left">Pa</td>
+</tr>
+<tr class="odd">
+<td align="left">Poisson ratio (bulk)</td>
+<td align="left">$0.27$</td>
+<td align="left">-</td>
+</tr>
+<tr class="even">
+<td align="left">Biot coefficient</td>
+<td align="left">$0.9$</td>
+<td align="left">-</td>
+</tr>
+</tbody>
+</table>
+
+The time period of 86400 is discretised into 100 steps.
+
+The distributions of pressure and displacement at the end time are shown in the
+ following figure:
+{{< img src="../nodal_source_test.png" >}}
\ No newline at end of file