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-   -   Moving Mesh Fluent (http://www.cfd-online.com/Forums/fluent/96407-moving-mesh-fluent.html)

ChrisR January 22, 2012 06:30

Moving Mesh Fluent
 
Hey there!


I wanna simulate a cylinder motion in Ansys Fluent but i always get the "negative element"- error.

I got 1 rigit body call "bottom", and the sidewalls call "wall" as deforming body.

The moition works and looks like the picture below :

http://imageshack.us/photo/my-images...enannt1wy.jpg/


I'm pretty new to fluent and don't know whats my failture is



I think it looks like my wall move but my domain is stationary and thats the reason why my fluid domain is outside the walls? Correct me if i'm wrong.

I think i got a major issue in my understanding of the moving mesh :-)

Is there any good tutorial for moving mesh?
Quote:




Updating solution at time level N... done.

Updating mesh at time level N...
Info: Maximum Cell Skewness outside reasonable limits, using 0.7 instead.
global conserved variables:
domain 1: ( 6.44971e-04 0.00000e+00 2.04581e-06 2.24282e-03 4.28291e-06 0.00000e+00 7.41762e-04 0.00000e+00 0.00000e+00 )
global conserved variables:
domain 1: ( 6.44971e-04 0.00000e+00 2.04581e-06 2.24282e-03 4.28291e-06 0.00000e+00 7.41762e-04 0.00000e+00 0.00000e+00 )done.

Warning: non-positive volumes exist.

Error: Update-Dynamic-Mesh failed. Negative cell volume detected.
Error Object: #f

Cola1988 January 22, 2012 17:03

I think i now the problem but i have no solution
 
Hey Dude,

I think I know your mistake.

It looks like your mesh doesn't deform. Your boundary ( piston bottom) simply moves up- and downwards. Is this assumption correct?

I think you have to couple the cylinder wall and the piston bottom to make the same movement. I think the mistake is somethng with your domain nd the moving mesh. Have you looked on re-meshin elemnts and so on?

Regards Phil

ChrisR January 22, 2012 17:05

Correct.

How can i fix it? Does anybody know?

Sugajen January 24, 2012 02:33

Hi there
I'm new to Fluent. Trying to move a piston by applying pressure. How should i do it?


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