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-   -   Propeller cavitation with non condensable gas(first constant property then ideal gas) (https://www.cfd-online.com/Forums/cfx/148308-propeller-cavitation-non-condensable-gas-first-constant-property-then-ideal-gas.html)

CFD-fellow February 9, 2015 04:47

Propeller cavitation with non condensable gas(first constant property then ideal gas)
 
Hi
Im modeling cavitation on a propeller with a constant volume fraction of air.After a procedure I got converged solution with reasonable results.
Now when I change air to ideal gas (with isothermal heat transfer) or define an expression for variable density with the previous run as initial value, I get overflow error on the first time step.
B.C:velocity inlet and opening with static pressure.
tstep=0.0001

Ive also decreased time step to 10e-9 which didnt help.
Decreasing relaxation factors caused overflow happen later(on 6th tstep)
Any idea?

ghorrocks February 9, 2015 05:23

I have attempted a similar simulation previously and never got it to work either. I never looked into it very hard, but you can expect to have a hard time getting this to converge (as you have found). I can only recommend trying some of the solver expert parameters and other solver settings and see if they help, otherwise contact ANSYS and see if they can help you.


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