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May 27, 2003, 13:30 |
COnvergence Problem !!!!
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#1 |
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Hello
I'm using VOF (water + air) model Geo-reconstruct, PISO, PRESTO, with good mesh (skewness <0.82) The problem is : all equations converge very well whereas COntinuity still oscillating about 0.003!!! does any one know why? or how to resolve? Thanks in advance Mohamed |
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May 27, 2003, 15:37 |
Re: COnvergence Problem !!!!
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#2 |
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did you try smaller under-relaxation factors?
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May 28, 2003, 03:56 |
Re: COnvergence Problem !!!!
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#3 |
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Hi Liu and all,
For which parameters should I reduce this under relaxation factors. I worry that computation will become very much slow with a small time step (0.0001) and smaller under relaxation factors !!! Is there any rules in modifying these under relaxation factors. I know only that for momentum and pressure , the sum should be 1 (0.3 + .07 for example) Thanks In advance, Mohamed |
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May 28, 2003, 04:35 |
Re: COnvergence Problem !!!!
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#4 |
Guest
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HI!
I think the best for you is to chech the messages on forum - there has been A LOT of discusions about convergence with VOF model. And don't play to much with undre relaxation...if you decerase them to much, your solution will converge but it will take a very long time and the solution might be wrong. I think 0.3 is the minimmunm. Regards MATEUS |
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