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-   -   How to decide Courant number as solution progresses? (https://www.cfd-online.com/Forums/ansys/228143-how-decide-courant-number-solution-progresses.html)

narendrapatel111 June 21, 2020 10:06

How to decide Courant number as solution progresses?
 
Hello, ##Fluent.

I am using pressure based solver, implicit scheme, VOF method (solving steady state open channel flow), k-e-RNG, and Coupled algo. Initially, I assigned Courant number = 10 and got flow field but residual for continuity is not dropping in the order of 10^-5. Also, I have mass imbalance problem (mass inflow is not matching with mass outflow). For coarser mesh, I didn't face mass imbalance problem but to improve results, I have refined mesh, and this unexpected problem showed up. I am using under relaxation factors 0.3. Is it due to inappropriate value of Courant number? Any suggestion to drop the residual of continuity and get mass balance?


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