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-   -   Mesh keeps folding, Help? (http://www.cfd-online.com/Forums/cfx/105020-mesh-keeps-folding-help.html)

A5729 July 20, 2012 13:03

Mesh keeps folding, Help?
 
Ok i suck , I'm trying to set up a rigid body simulation of a hollow cylindrical shaped hull of a boat , although i am stuck with a few things , as ever, help makes you awesome.

I keep getting an error message saying that my mesh has folded or something like that. This goes away instantly as soon as i turn off the motion parameters.

Are there particular faces i need to set up that link with the mesh?

Additional pics can be provided
http://i1265.photobucket.com/albums/...uidFlowCFX.png

ghorrocks July 20, 2012 18:18

It is MUCH harder to do this type of simulation as a rigid body. It is much easier to assume the floating body position and see what lift/drag you get at that position. You can then refine the body position if the lift or drag say it should be adjusted a bit.

Then the simulation becomes a series of fixed mesh simulations. This is much easier than a single rigid body motion simulation.

A5729 July 23, 2012 04:08

Thanks for the reply , but i'm trying to do waves too, also trying to find the floating body position and a multitude of other things , so i need to learn how to do rigid body

swelltimes July 23, 2012 04:34

have you tried the buoy tutorial and mesh stiffness?

A5729 July 23, 2012 04:53

Yeah my mesh stiffness is an enormous number , Unless it should be small?

swelltimes July 23, 2012 06:46

yeah, pretty sure. otherwise your cells vanish = folding, no? pretty sure youll find your answer in the buoy tutorial..

cheers

A5729 July 23, 2012 07:36

Are there any particular design points that change by using a 3d problem?

A5729 July 23, 2012 11:29

Ah i think the issue is the Timestep size , Am putting it down to a lower value, It made a difference on the Bouy tutorial.


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