[Vivio]

Hi everyone,

I am doing a simulation of the cavity case and want to find the location of the centre of the vortex. One way to do this is using the streamFunction function object and finding where the stream function is a minimum. I am using swak so my function looks like this:

streamFunction {
            type expressionField;
            autowrite true;
            expression "streamFunction(phi)";
            fieldName streamF;
        }

        minStreamFunctionPos {
            type swakExpression;
            verbose true;
            outputControlMode timeStep;
            outputInterval 1;
            expression "streamF";
            valueType internalField;
            accumulations (min);
        expression "minPosition(streamFunction(phi))";
        }

This works for a single grid. However if I try to do this for an overset case, or another case with multiple grids, I get the following error message.

FOAM FATAL ERROR: 
Cannot find initialisation face or a cell.

    From function streamFunctionPluginFunction::doEvaluation()
    in file streamFunctionPluginFunction.C at line 253.

I also get the same error if I try and use the streamFunction function object included in ESI-OpenFOAM. It looks from the source code like it's trying to find a face on which the flux is zero and can't find one.

Any idea what might cause this, and if there is a workaround?

Best regards,
Vivio

[Wowbagger]

...maybe too late for the original query but maybe it helps anyway in the future.


I just had this problem in a potentialFoam case.
After some trial and error I found out that the velocity is related in my case.

Switching the initial velocity to higher values is one option as it does only scale the result.

The other solution is to set the wiritePrecision to a higher value. I did from 6 to 12.
Worked in my case.



Best regards
Michael