turbulence models for two different fluids
 

hi all, i want to ask that for analyzing two-phase flow, can it be possible in fluent to give two different turbulence model for the two phases/fluid. say one fluid is in laminar state while other is in turbulence mode. how can i apply this condition to the two-phase flow problem.

thanks for the reply

regards, mvee

Re: turbulence models for two different fluids
 

i am not sure but what you can do it is to set up your turbulent model and then in the boundary condition you set up 0 for the turbulence of your laminar zone

Re: turbulence models for two different fluids
 

hi ritmat, have u tried with this? one question arises, that if by keeping turbulence in boundary condition to zero then what is the need to give additional laminar model in define-viscous menu. all the time to define laminar flow, why donot we directly define it through zero turbulence in bc?

thanks for ur reply, mvee

Re: turbulence models for two different fluids
 

good question, but i think it is maybe only a cost of time. If it uses equation of turbulence , even with a zero it will have to run more to resolve it than if it is using laminar flow equation. Thats my answer maybe some one can tell us more about that

Re: turbulence models for two different fluids
 

ya thats right, please throw light on this topic

Re: turbulence models for two different fluids
 

If you break your domain up into two volumes, one being your laminar region and the other where you expect turbulent flow, then this is very easy. Select your laminar region in the boundary conditions menu and select the 'Laminar Zone' option. Make sure to set the face separating the two domains to interior.

Re: turbulence models for two different fluids
 

ya will, thats fine but whatever solution that u propose is possible only when we know that in this region there is air and in remaining region there is water. I do not know the proportion of the different phases in the total domain selected for simulation. how can i decide that this domain is for this phase and that ultimately represents laminar region and another domain represent second phase which is in turbulent mode? Is that clear?

thanking you mvee

Re: turbulence models for two different fluids
 

hi!

I never tried this, but you may use two fluid zones - one turbulent and one laminar. The bondary between those both zones may be modeled by an adaptive mesh...

So you have your mesh moving like the boundary - e.g. for water waves, the fluid volume will follow every wave...

Youst like modeling solit-fluid interaction of e.g. a flag in the wind...

As I said, that is just a crazy idea!

Ralf

Re: turbulence models for two different fluids
 

Sorry about that, I only skimmed your question and didn't read thoroughly enough.

Re: turbulence models for two different fluids
 

Dear Ralf and Will, ya will try with adaption scheme. I really donot know @ adaption but will try. Let i will explain my problem. initially, water is flowing through the pipe. and then air is injected into the pipe. so the proportion of the air means volume fraction of air in pipe depends upon the mass flow rate of air and water. I have to simulate this condition. can u suggest in this regards?

Please

thanking you mvee