[CellZone]

Hi,

I have a big stl file as geometry. After I used snappyHexMesh I use transformPoints to scale it (0.001 0.001 0.001) to meters.

When I run my simulation I would like to plot the pressure over a specific surface. Therefore I created a stl surface and I use swakExpression in Control Dict to analyze the pressure like this:

inlet_pressure
{
type swakExpression;
outputControlMode timeStep;
outputInterval 1;
valueType surface;
surfaceName Inlet;
surface {
type sampledTriSurfaceMesh;
surface Inlet.stl;
source cells; // What to sample: cells (nearest cell)

interpolate false;
}
expression "p";
accumulations (average);
verbose true;
}

Normally this is working fine, but:

Since I scale my geometry first, I can not import my stl surface, since it is of other dimensions. Therefore I tried to scale my stl surface by using: surfaceTransformPoints -scale "(0.001 0.001 0.001)" inlet.stl inlet2.stl

There is no error but this is not working fine because my new geometry (surface) does not have the same origin as my geometry of snappyHexMesh.

One way to fix this would be, to measure my geometry of snappyhexmesh and create a proper surface with the right dimensions and origin. But this seems to be not a neat solution.

Do you have any suggestions to solve the problem?

I can not import the stl file surface, use snappyHexMesh, use transformPoints , since my new surface would be recognized as a wall in the fluid region.

I hope you can follow me

Thank you!

[RobinZ]

You can scale your stl with the surfaceConvert utility.
Use the -scale option. The command should look like:
surfaceConvert -scale 0.001 inlet.stl inlet2.stl

An advise here:
you can use simpleFunctionObjects to postprocess fields on patches just in time...

regards

Robin