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Blub August 2, 2013 05:26

potentialFreeSurfaceFoam extract zeta
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Hi everyone,

I am trying to extract the free surface elevation from the oscillatingBox tutorial which uses potentialFreeSurfaceFoam.
I added the following probes to my controlDict


libs (

fieldsOfInterest (

functions {
    someProbes {
        type probes;
        probeLocations (
            (4.0  1.0  0.0)
        fields $fieldsOfInterest;
    aLine {
        type sets;
        outputControl outputTime;
        fields $fieldsOfInterest;
        interpolationScheme cell;
        setFormat raw;
        sets (
            lineUp {
                type midPointAndFace;
                axis y;
                start (2 1 0);
                end (10 1 0);

The probes create an output for p, U and zeta but the entries for zeta are always 0. But when I check the same Line in paraFoam with plotoverLine they are not 0.

Do I have to include another option for extracting zeta or is there a better way?
I first tried to use but I could not get non averaged values.

Thanks for any suggestions.

Benji April 22, 2014 10:31

Sorry for digging this up, but I'm currently stuck with a similar problem.

I'd like to extract zeta that is calculated with potentialFreeSurfaceFoam. When I plot zeta in paraView (so far I haven't used sampleDict), I can see the values (for example on the wireframe) for zeta. But as soon as I try for example Plot over Line or the view in the Spreadsheet, the values for zeta are all zero. Does anyone know why? I'd really appreciate some help.


davibarreira February 25, 2015 22:20

This post is quite old, but perhaps if you still want to know... The reason your sample line shows zero is that the "zeta" values are present only in the boundary face "free surface", and the "sample line" function in Paraview will try to interpolate the values in the cells.

If you want to see the surface deformation in Paraview, use the filter "Wrap by vector", select "zeta" as your variable and set a high value for the scale factor, such as 1000.

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