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-   -   Warning: negative cell volume detected! (http://www.cfd-online.com/Forums/fluent/47111-warning-negative-cell-volume-detected.html)

boboroo January 23, 2008 22:46

Warning: negative cell volume detected!
 
hi, i use dynamic mesh in my model of a sway tank. the tank is filled with water.

i load a time-dependent angular velocity to the tank walls.

then, i set the time step 4e-5, and after 500 steps, the warning is shown: Warning: negative cell volume detected! Error: Update dynamic mesh failed! Error Object: ()

anyone could tell me what is the problem. thanks in advance!

shehab abdelrahman January 23, 2008 23:09

Re: Warning: negative cell volume detected!
 
I'm not quite sure of that. but i guess your dynamic mesh has been deformed or squeezed until the edges of some or all the cells has interfered within the same cell. this is the definitions of the negative cell volume error. you need to improve your initial mesh to be not too angular and use structured mesh if possible. also you may increase the mesh size to account for the deformation displacement during the iteration until reaching the convergence without having negative mesh. I hope this will help

boboroo January 24, 2008 01:29

Re: Warning: negative cell volume detected!
 
thank you very much! i will have a try.

mAx January 24, 2008 02:17

Re: Warning: negative cell volume detected!
 
are you using layering/smoothing or remeshing method for the dynamic mesh?

Sham January 24, 2008 09:53

Re: Warning: negative cell volume detected!
 
Try with smaller time step or use a triangular mesh as it is better for MDM simulation. If this still does not work, you have to check your parameters in defining MDM.

Sham


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