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spk November 29, 2011 05:36

under relaxation factors
 
Hi everyone,

I simulate a hydrofoil under non-cavitating conditions using Flunet.
The under-relaxation factors that i use are:
pressure 0.8
density 1
body forces 1
momentum 0.2
turbulent kinetic energy 0.8
turbulent dissipation rate 0.8
turbulent viscosity 1
Also i use Simple algorithm and k-ε standard

I want to converge Cl and Cd. After a great number of iterations Cd and Cl change value every ten iterations. If i change the under-relaxation factors
and define all of them with the value 0.01, i see that Cd and Cl dont change any more!
Is that right movement? I change under-relaxation factors and i have convergence?

Thanks,
spk

emreg November 29, 2011 05:57

you have to use URF when your work cant be converged.
if your simulations isnt so complex that it has transient behaviour, u dont need to modify URF.


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