add UniformScalarField monitor documentation (!81)

docs/source_docs/user_guide/inputs/output/monitors.rst

@@ -203,6 +203,31 @@ The following table lists all the fluid phase variables that can be monitored:
 +--------------------------+-----------------------------------------------------------------------------------------+
 
 
+Uniform Scalar Field
+~~~~~~~~~~~~~~~~~~~~
+
+The following table lists all the fluid phase space-uniform variables that can
+be monitored:
+
++--------------------------+-----------------------------------------------------------------------------------------+
+|                          | Description                                                                             |
++==========================+=========================================================================================+
+| thermo_p_g               | fluid thermodynamic pressure                                                            |
++--------------------------+-----------------------------------------------------------------------------------------+
+
+For a uniform scalar field, the monitor data value is simply the value of the
+variable at current time:
+
+Value
+   +-------------------------------------+
+   | Eulerian::UniformScalarField::Value |
+   +-------------------------------------+
+
+   Returns the value of the field quantity in the selected region.
+
+   .. math:: \phi_{ijk}
+
+
 Point Region
 ~~~~~~~~~~~~