CFD Online Discussion Forums - Runtime sampling of line

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Runtime sampling of line

Hello openFoam community,

I have a problem that I am trying to solve with sampling of field variable over a line. What I would like to do is to add a piece of script into my controlDict so that I can obtain the sampled fields during runtime at the same interval as the timestep. I can easily use sampleDict and the command sample to do this after the simulation has finished but I would like to achieve a much higher sampling frequency than just the write output.

At the bottom of my controlDict I have written:

Code:

functions {

   WG9 {

      type sets;

      functionObjectLibs ("libsampling.so");

      setFormat raw;

      interpolationScheme cell;

      outputControl timeStep;

      outputInterval 1;

      axis    z;

      start   (10.369 2.05 0);

      end     (10.369 2.05 1.15);

      nPoints 100;

      fields (alpha1);

   }

}

It seems to run fine without any errors but there is no output folder (I would expect a postProcessing folder to appear after simulation starts much like it does when you run the "forces" function)

Does anyone know if this is even possible what I am trying to accomplish? If so, do I appear to be missing something?

Steven

Hello all,

Just for reference I would like to post the solution I have found. Actually, it was someone elses solution I adapted to my own case (found here http://www.cfd-online.com/Forums/ope...ampledset.html), but it eluded me for a good few days.

To sample a field along a user-specified line with an output frequency equal to the time step I added this to the bottom of my controlDict:

Code:

functions {

alpha1 //call this whatever you like

  {

    type sets;

    enabled true;

    verbose true;

    interpolationScheme cellPoint;

    outputControl timeStep;

    outputInterval 1;

    setFormat raw;

    fields (alpha1); //insert the fields you would like to sample

    sets

    (

      WG9 //give the line a name. You can add more sample lines below this one

      {

        type uniform;

        axis z;

        start (10.369 2.05 0);

        end   (10.369 2.05 1.15);

        nPoints 100;

      }

    );

}

  }

I didn't have to add any function object libraries which seems odd to me :confused:. Works just fine though.

Cheers,
Steven