snak4foam/groovyBC problem
 

Hi All,

I have a strange problem with setting boundary using groovyBC.

The solver used is modified Laplace solver. The aim is to elaborate more complicated Neumann type boundary, but I face the problem with using groovyBC at the very beginning during, testing phase after installation.

The boundary for testing was set with:

...
upperWall
{
type groovyBC;
fractionExpression "0";
gradientExpression "vector(0,0,0)";
}
...

During evaluation for the first timestep solver generates the error:
"--> FOAM FATAL ERROR: The expected return type scalar is different from the stored result type "vector"".

What this error message is about?

OpenFOAM-boundary conditions (and therefor groovyBC too) mean with "gradient" "gradient in the direction normal to the patch". So if your field is a scalar then this gradient is a scalar too (contrary to what you'd expect in "normal mathematics")

Dear Bernard,

thank you very much for your explanation. Now it is clear. I proceed with the work.