[Mark JIN]

Dear Friends,

I wonder if anyone has ever tried to calculate average weighted value (ie. velocity) at localized plane within your domain? I found there were ways to calculate average weighted value at defined patch, but what if I want to do that anywhere else?

Just as what I showed in the attached pics. If I want to calculate average wind velocity at the highlighted plane (in black), how can I achieve that? Should I define coordinates of the plane I want to calculate in Controldict?

Pls bear with me if I repeat my questions so many times.
Appreciate in advance for any help.

Regards,
MarkJIN

[alexeym]

Hi,

Let's assume, you are using OpenFOAM 4.x. Did you try surfaceRegion function object? (See http://cpp.openfoam.org/v4/a02578.html#details).

There is an option to take field values from sampledSurface, you can average values.

[Mark JIN]

Originally Posted by alexeym

Hi,

Let's assume, you are using OpenFOAM 4.x. Did you try surfaceRegion function object? (See http://cpp.openfoam.org/v4/a02578.html#details).

There is an option to take field values from sampledSurface, you can average values.

Dear Alexey,

Thanks for your guide. I'm using openfoam 4.1. I havent try surfaceRegion before. Is this function working when running xxFoam or working during postprocessing? Btw, where can I define the coordinates of my user defined face to be averaged? I'm quite new to openfoam and cannot understand the structure of dictionaries sometime.

Regards,
Mark

[alexeym]

Hi,

If is still relevant,
- it can be run both ways, since it is function object.
- definition of sampledSurface can be learned from:
1. https://github.com/OpenFOAM/OpenFOAM...es/controlDict
2. If you need plane, then maybe cuttingPlane instead of sampledTriSurfaceMesh if better choice, definition can be found, for example, here: https://github.com/OpenFOAM/OpenFOAM...m/cuttingPlane

[Mark JIN]

Originally Posted by alexeym

Hi,

If is still relevant,
- it can be run both ways, since it is function object.
- definition of sampledSurface can be learned from:
1. https://github.com/OpenFOAM/OpenFOAM...es/controlDict
2. If you need plane, then maybe cuttingPlane instead of sampledTriSurfaceMesh if better choice, definition can be found, for example, here: https://github.com/OpenFOAM/OpenFOAM...m/cuttingPlane

Dear Alexey,

Thanks for your links, seems relevant.

Best regards,
Mark

[heru]

finally,



how did you selected an area an then did the average of a field u?

[eb19]

Originally Posted by alexeym

Hi,

Let's assume, you are using OpenFOAM 4.x. Did you try surfaceRegion function object? (See http://cpp.openfoam.org/v4/a02578.html#details).

There is an option to take field values from sampledSurface, you can average values.

Hi Alexeym,

How can we average a value using sampledSurface? I need to calculate force on an area inside my domain. The area is not a patch, so I can not use patchIntegrate or force. I also tried surface sampling, but I only got pressures at each point on the area, not with the cell area. Therefore, I can not quantify the force.

I also tried surfaceRegion, but I am not sure which operation should I use?
Do you know or have suggestions? I have been searching and trying for almost three days with this, but not yet seen a light. I would appreciate your suggestion. Thank you.

eb19