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Smaller element size caused problem in Acoustic-Shell Interaction
Posted Mar 13, 2014, 11:34 p.m. EDT Mesh Version 4.4 1 Reply
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I found an interesting result from COMSOL 4.4 Acoustic-Shell Interaction. Let me describe it here:
I have a 1 square meter cubic whose all 6 walls were set to Sound Hard Boundary except a A2 size window in the front wall where a 2.5 mm thick Aluminum Plate was mounted with 4 edges Fixed Constrained. Its a simple set-up. Then I just add the Acoustic-Shell Interaction physics and set the plate as the Exterior Shell. And I do a Eigenfrequency analysis.
Then comes the interesting thing. If I set the mesh size to "Normal", COMSOL will give out a reasonable result with the first coupling mode caused by the plate around 95Hz. But if I set the mesh size to "fine", there will be several local modes under 95Hz, which should not be real.
Why should this happen? How can I get a more accurate result for the acoustic-structure interaction analysis in COMSOL?
I have a 1 square meter cubic whose all 6 walls were set to Sound Hard Boundary except a A2 size window in the front wall where a 2.5 mm thick Aluminum Plate was mounted with 4 edges Fixed Constrained. Its a simple set-up. Then I just add the Acoustic-Shell Interaction physics and set the plate as the Exterior Shell. And I do a Eigenfrequency analysis.
Then comes the interesting thing. If I set the mesh size to "Normal", COMSOL will give out a reasonable result with the first coupling mode caused by the plate around 95Hz. But if I set the mesh size to "fine", there will be several local modes under 95Hz, which should not be real.
Why should this happen? How can I get a more accurate result for the acoustic-structure interaction analysis in COMSOL?
1 Reply Last Post Mar 15, 2014, 11:03 p.m. EDT
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Posted:
1 decade ago
But if I do a Frequency Domain frequency sweep excitation, the result won't be sensitive to the element size any more... Who can give me some clue about how should this happen?