Convergance of turbulence intensity
 

I have problem of convergance of tubulence intensity and disspation after 100 iteration it is remainig costant 1.22e-2for turbulence and 2.52e-2 for disspation I setted under relaxation factor for turbulance and disspation 0.3 .I am using the high renoylds number model for steady state incomprissible flow.Turbulence intensity is 5% and length 0.0266.Can anybody help me to solve this problem/

Regards subhash

Re: Convergance of turbulence intensity
 

It depend on your boundary condition. I don't know exactly your CFD geometry. Maybe your boundary conditions for outlet is set too closed to the inlet or the k and e value at your pressure boundary is not correct. hope it be helpful.

Re: Convergance of turbulence intensity
 

Dear Sir Boundary condition at inlet and oulet are not too close it is around 0.8m its a geometry of engine manifold.And abound k-e value i don't have measured value so i had taken it from literature.Now also i have same problem of only k-e conversion.

Thank you for reply subhash

Re: Convergance of turbulence intensity
 

Perhaps that's the best that you can do on this grid. Try changing the turbulence intensity to 10% and the length scale to 10% of the inlet "diameter" and see if there is any difference. You could also try changing the default iteration convergence criteria from 0.1 to 0.001 say and see if this makes any difference.

If your residuals on k and ep are not falling even after changing the above then this is probably the best you can do on that grid for these boundary conditons.

allan