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FSI tutorial: Warning: Inverted mesh element near coordinates

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I downloaded the FSI example from website.
Fluid-Structure Interaction
Model ID: 361
www.comsol.com/model/fluid-structure-interaction-361

It is a classic problem.
It looked good. But when I only changed the inlet velocity from u_mean to U.
It returned Warning: Inverted mesh element near coordinates and failed.
After I tried different velocity number, from 1 m/s to 0.0001 m/s, it finally converged.
But 0.0001 m/s was meaningless to me.

Does anyone knows what happened in this problem?

3 Replies Last Post 22.09.2013, 16:12 GMT-4
Mustafa Abd El-Mageed

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Posted: 1 decade ago 17.09.2013, 14:16 GMT-4
Dear Junxiang,
I think the problem with the scaling , please see that
www.comsol.com/community/forums/general/thread/25283
thanks a lot
Dear Junxiang, I think the problem with the scaling , please see that http://www.comsol.com/community/forums/general/thread/25283 thanks a lot

Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 19.09.2013, 08:53 GMT-4
Dear Junxiang,

When you change the velocity from u_mean to U you create an instantaneous change in inlet velocity in a transient problem. That causes problems. You can use “U” successfully in the inlet velocity term if you switch to a Stationary study.

Nagi Elabbasi
Veryst Engineering
Dear Junxiang, When you change the velocity from u_mean to U you create an instantaneous change in inlet velocity in a transient problem. That causes problems. You can use “U” successfully in the inlet velocity term if you switch to a Stationary study. Nagi Elabbasi Veryst Engineering

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Posted: 1 decade ago 22.09.2013, 16:12 GMT-4
Thank you very much!

Now I know how to modify this case.
Thank you very much! Now I know how to modify this case.

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