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Old   June 1, 2010, 04:40
Default unsteady divergence simple case
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Francis
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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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Old   June 9, 2010, 08:21
Default Timestep control
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Hans Bihs
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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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Old   June 10, 2010, 04:24
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Francis
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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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