[Adam_K]

I am using the chtMultiRegionFoam solver to look at transient conduction through multi-phase systems. The simulations are running correctly and I am able to visualize the temperature maps using Paraview, however I would like to be able to see the thermal gradients as well.

When I apply the Gradient of Unstrcutred DataSet filter in Paraview I get the following error:

ERROR: In C:\bbd\ecd3383f\build\superbuild\paraview\src\VTK\Filters\General\vtkGradientFilter.cxx, line 318
vtkGradientFilter (00000205FBC4A420): No input array. If this dataset is part of a composite dataset check to make sure that all non-empty blocks have this array.

ERROR: In C:\bbd\ecd3383f\build\superbuild\paraview\src\VTK\Common\ExecutionModel\vtkExecutive.cxx, line 782
vtkPVCompositeDataPipeline (00000205F4C65220): Algorithm vtkGradientFilter(00000205FBC4A420) returned failure for request: vtkInformation (0000020592472820)
  Debug: Off
  Modified Time: 19414550
  Reference Count: 1
  Registered Events: (none)
  Request: REQUEST_DATA
  FROM_OUTPUT_PORT: 0
  FORWARD_DIRECTION: 0
  ALGORITHM_AFTER_FORWARD: 1

In the T file, I can see the following lines, so it looks like a gradient has been calculated (although I don't see a direction associated to these magnitudes).:

        refGradient     uniform 0;
        valueFraction   nonuniform List<scalar> 
1520
(
0.0033887263
0.0033894414

Can anyone point me in the right direction? I have seen some cases where people need to modify the solvers itself in order to export certain fields but for something as simple as dT/dx, dT/dy and their magnitude it seems like there should be an easier way.