[McReijen]

Dear All,

In the case of a turbine in a duct I am trying to figure out how much energy the whole configuration is extracting from the flow. The strategy I came up with was calculating the total amount of total pressure times the volume flow at the inlet and at the outlet and the difference would approximate the amount of energy that went into the system or dissipated.

I place a patch at the inlet and the outlet and use the surface field value function with the weightedAverage operation and the phi as weight. The areas that are computed for both patches differ significantly. However I created the patches from geometry and they come from the same object so they should be equal.

In paraview the surface areas are the same size when I calculate it using the integrate variables filter.

So my question is how surface field value calculates the area. Or what am I doing wrong in applying the function?

The area given by paraview is 19.01 (which is correct) but surface field value calculates 15.59 m2 and 18.44 m2.

I'm using openfoam 5.x and simpleFoam, the patches are created using createPatch.

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