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-   -   Which Turb. Model is Suitable for Re=140000? (https://www.cfd-online.com/Forums/fluent/45967-turb-model-suitable-re-140000-a.html)

Mahbub September 8, 2007 05:04

Which Turb. Model is Suitable for Re=140000?
 
Dear

I am trying to simulate the flow over cylinder at Re=140000. I tried by some turbulent model, but didn't get good result. I tried to find Cd and the vortex shedding. Could any one please tell me, which model is suitable in this case ? Thanking all of you.

Mahbub


Jesse September 9, 2007 04:17

Re: Which Turb. Model is Suitable for Re=140000?
 
SST

Mahbub September 9, 2007 07:58

Re: Which Turb. Model is Suitable for Re=140000?
 
Dear Jesse

Thank you for your co-operation. I have used K-omega SST turbulent model but I didn't get the vortex shedding and my Cd=0.112 (that is far from experimental value). I use: u=1, mu=1, D=1, densiry=140000 to get Re=140000 also put k=0.00138, w=0.11, time step size=0.014.

Would you please give me any sugession?

Mahbub


Sham September 11, 2007 20:34

Re: Which Turb. Model is Suitable for Re=140000?
 
I think with such high Re, your time step size is large. Try setting your time step size so that you Courant number is less than 1 as I was told. Also amke sure your grid is fine enough at the critical region.

Mahbub September 12, 2007 08:13

Re: Which Turb. Model is Suitable for Re=140000?
 
Dear Sham

I used Time step size = 0.01, and the courant number = 0.7, isn't enough? I still confused to set Re number. When I change density to change Re then I get the result, but if I copy Water-liquid from fluent data base and change velocity to change the Re then I didn't get the result. I think Razvan can give me any suggestion. Could you please gibe me the mail address of Razvan?

Thanking you,

Mahbub



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