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Prescribed compression of fluid

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Hi,

I have a very simple model, consisting of a 1 x 1 m^2 square which is filled with Air.
I know that this problem can be solved by assuming ideal gas, and computing the area of the deformed domain. However, I want to combine this concept with more complex fluids, and therefor I want the Laminar Flow physics to solve this problem.

The study is Time Dependent.

I use the Deformed Geometry module to prescribe the deformation of my domain:
Attach Free Deformation to the whole domain, and apply a Prescribed Mesh Velocity to the top boundary, with prescribed y velocity of -0.05 m/s. The other boundaries are fixed (prescribed displacement of (0,0)).

It then fails: "Repeated error test failures. May have reached a singularity." when I try to run it.
Also, I see that the two sides of the square keep there height, but they have to shrink with the lowering of the top boundary.


3 Replies Last Post 2017年3月4日 GMT-5 14:18

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Posted: 8 years ago 2016年5月27日 GMT-4 06:19
I see I made a stupid mistake regarding the shrinking of the sides. I have solved that by prescribing the mesh displacements on the sides only in x-direction.

Now it compresses as I want to do it, but the pressure is not changed.
I see I made a stupid mistake regarding the shrinking of the sides. I have solved that by prescribing the mesh displacements on the sides only in x-direction. Now it compresses as I want to do it, but the pressure is not changed.


François Mandias COMSOL Employee

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Posted: 8 years ago 2016年5月27日 GMT-4 08:23
Dear Jort,

I suggest you adrress your post directly to: support@comsol.com

Best regards,
François Mandias
Dear Jort, I suggest you adrress your post directly to: support@comsol.com Best regards, François Mandias

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Posted: 7 years ago 2017年3月4日 GMT-5 14:18
Hi, Jort Jacobs,

Have you solved the problem? I also encountered a similar situation. Could you please give me some suggestions to achieve the compression at a constant rate?

Thank you so much for your help.

Yu
Hi, Jort Jacobs, Have you solved the problem? I also encountered a similar situation. Could you please give me some suggestions to achieve the compression at a constant rate? Thank you so much for your help. Yu

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