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June 1, 2010, 05:40
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unsteady divergence simple case
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#1 |
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New Member
Francis
Join Date: Apr 2010
Posts: 13
Rep Power: 16  |
im curently workin on a cylindrical obstacle in a pipe... i hav some convergence issues...my calculation is unsteady.
i really need help, regards |
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June 9, 2010, 09:21
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Timestep control
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#2 |
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Super Moderator
Hans Bihs
Join Date: Jun 2009
Location: Trondheim, Norway
Posts: 405
Rep Power: 19 |
Hei,
possibly your time step is too large. Especially if you use explicit time treatment or implicit time stepping without under relaxation, high CFL numbers (CFL>1) cause numerical instability. In case you use your own program and have access to the source code, consider adaptive timestep control. Regards Hans |
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June 10, 2010, 05:24
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#3 |
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New Member
Francis
Join Date: Apr 2010
Posts: 13
Rep Power: 16 |
my parameters are fine. i changed the URF's and it is workin but i had to increase the inner iterations...at least it is converging even if itll be longer
by the way im using implicit scheme with URF's regards, Francis |
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