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Eigenfrequncy with liquids

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Hy all

I try to solve the following problem: In a container will be full some liquid. On the top, i will have a flexible membrane as a lid. With a ring out of a hard material, i gonna then press from the top onto this membrane an get like this a deflection (because the liquid in the container is constant). Hopefully you can imagine what i mean ;-)

To find out the deflection was not a problem. I used the fluid-solid-interaction physics. But now i would find the eigenfrequencies of my system. Unfortunately i saw that there is no such application in this physics... What do you propose me to use? Is there any possibility to compute them with this physics? Or do i have to use another one? Is there another physics where i can implement a solid container with a liquid in it?

I am really new on COMSOL an therefore dont understand a lot about it.Thank u already now for helping.

Best regards
fabian

1 Reply Last Post 2012年11月2日 GMT-4 06:01
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2012年11月2日 GMT-4 06:01
Hi

this is a common problem, I see, unfortunately FSI is not set up for eigenfrequency or Frequency domain analysis, I believe that you need the acoustics module to provide the correct fluid load onto the membrane (but I do not have that module ;)

In a first approximation you could load your lower boundary with an additional mass, representing the fluid volume displaced but as you have a closed fluid volume it's more complex than that.

I would also appreciate to see some good models proposing such solutions ;)

--
Good luck
Ivar
Hi this is a common problem, I see, unfortunately FSI is not set up for eigenfrequency or Frequency domain analysis, I believe that you need the acoustics module to provide the correct fluid load onto the membrane (but I do not have that module ;) In a first approximation you could load your lower boundary with an additional mass, representing the fluid volume displaced but as you have a closed fluid volume it's more complex than that. I would also appreciate to see some good models proposing such solutions ;) -- Good luck Ivar

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