Elmer Discussion Forum

Hi everyone,

I am looking for a solution that will allow estimating drag (pressure acting on the surface) created by a simulated shape.

Exactly the same as discussed in https://www.youtube.com/watch?v=J944HOj_4b0&t=0s.

However, I cannot find how to group nodes/elements on specific surfaces due to the geometry of the model.

I am using Salome to group geometries in 2D simulation. Elmer sees these groups, however, I cannot extract them to ParaView.

Is it possible in the Elmer?

Thanks,
Mateusz

Hi

I suggest you use "Calculate Loads = True" and then appropriate "boundary sum" operator in SaveScalars module. You may need to do this component-wise to "Flow Solution Load i", i=1,2,3. This will get you the most accurate force estimation possible that includes also drag effects.

edit: There seems to be a test case "RotatingBeamFlow" that computes the total force. It uses concept of "Component" which is not so often used. It comes from electromagnetics where it makes sense to define components having lumped features like capacitance etc. However you can also group boundaries of Navier-Stokes solution and have them constitute a "component".

https://github.com/ElmerCSC/elmerfem/tr ... ngBeamFlow

-Peter

Yes, it works!
Thanks a lot!

Hi Mateusz,

Perhaps you could share the sif for those facing the same challenge in the future.

-Peter