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-   -   Do I need PRESTO!?, Body force weighted or ?? (http://www.cfd-online.com/Forums/fluent/46183-do-i-need-presto-body-force-weighted.html)

jrg September 29, 2007 23:38

Do I need PRESTO!?, Body force weighted or ??
 
Hi. I have a jet hitting a wall before leaving the outlet located at one end of the wall. Between the impingement point and the outlet, there are some swirls. Flow is incompressible and laminar.

In this case, should one apply a more elaborate pressure discretization scheme? I used the standard scheme and the outlet pressure is off by 20% compared to expt data. When I tried PRESTO!, solution diverges.

jrg September 30, 2007 18:38

Re: Do I need PRESTO!?, Body force weighted or ??
 
To elaborate further, I also use the SIMPLEC. When in combination with PRESTO and with skewness correction of 1 or more, solution diverges. Without skewness correction, convergence can be achieved.

The question now is if skewness correction is necessary? Does it change the solution or does it affects only convergence speed?. The mesh is an unstructured hex.

If I use body force weighted, I can get a stable solution even with some skewness correction.

Can someone make sense out of these observations?

Bionico August 31, 2012 10:33

PRESTO! or BFW ??
 
Hi everybody,
I'm modeling a heat source in a closed room. My mesh is quite dense: 4M tetra (around the source) and 4k Hexa (far from the source).
Can anybody tell me which discretization method for pressure is better? PRESTO! o BODY FORCE WEIGHTED? What are the differences between them?

Thanks in advance :)

Bionico September 3, 2012 07:38

I read something about the presence of corners: for this reason PRESTO! should be better. Can anyone confirm it?


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