Evaluate Points and lines in BEM Domain

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I try to evaluate a loudspeaker in 3d, axissymmetry is not possible due to changes to the model that will come.

I have been able to solve the problem in a 2d axissymmetric model. I evaluate the sound pressure level in points in a 2 m radius around the loudspeaker.

In 3d the fem model became too large and ran out of ram.

Now I need to set up a 3d evaluation with bem.

I have tried to mesh the points and lines (when rotate) around the loudspeaker and use the average nonlocal coupling to evaluate pabe.Lp. i have also given these points air as material. Unfortunately the sound pressure level is not correct as it is constant and does not change with frequency.

When I evaluate - Expression: at3_spatial(2[m],0,0,pabe.p_t,'minc') as 1d plotgroup and as octave band it works. It is the correct solution (same as in FEM 2d axissymmetric solution)

When I evaluate at3_spatial(2[m],0,0,pabe.Lp,’minc’) as 1d plotgroup in a global evaluation it does not work in any combination.

Evaluation avg0deg(pabe.Lp) gives me a flat line though it should be the same as the octaveband.

How can I evaluate sound pressure at specific points or as averages over lines? Is there any ways to correctly include the meshed points i used?

Thanks in advance.



1 Reply Last Post Jan 31, 2025, 7:41 a.m. EST
Henrik Sönnerlind COMSOL Employee

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Posted: 5 days ago Jan 31, 2025, 7:41 a.m. EST

Would it be possible for you to attach a simplified example? That would probably increase the chances that you get an answer significantly.

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Henrik Sönnerlind
COMSOL
Would it be possible for you to attach a simplified example? That would probably increase the chances that you get an answer significantly.

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