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-   -   Half laminar and turbulent model trying to solve (http://www.cfd-online.com/Forums/fluent/48258-half-laminar-turbulent-model-trying-solve.html)

Andrew Clarke May 16, 2008 09:56

Half laminar and turbulent model trying to solve
 
Hi there. I am currently dealing with a problem where the fluid flows into a radial gap (laminar flow here - part one) and exits into an axial channel in turbulent conditions (part two).

I have tried solving the full model using K epsilon realizable but the results do not make sence.

I then tried to create the first part of the model in laminar (result on laminar part good) and then created the second part as turbulent using inlet velocity values here from velocities at the outlet of the first part (this is when results go crazy)... can this be done?

If not, is it possible in fluent to solve one half of the model in laminar and the second half in turbulent? Or is there a better solver that can be used for these radial jets entering the turbulent region?

Any suggestions at all on this would be gold to me... many thanks for your time reading this...

red lemon May 16, 2008 17:51

Re: Half laminar and turbulent model trying to sol
 
separate fluid zones and define one as laminar (tick box in fluids panel). Turbulence quantities will be transported through laminar zone but no generation or dissipation.

Andrew Clarke May 17, 2008 07:00

Re: Half laminar and turbulent model trying to sol
 
Many thanks. I will try that. I will post another reply as soon as I get results on the procedure to let you know.

Andrew Clarke May 19, 2008 11:52

Re: Half laminar and turbulent model trying to sol
 
I have looked in the fluid panel and i cannot find anywhere where I can define laminar or turbulent... I am using Fluent 6.3

Andrew Clarke May 19, 2008 13:22

Re: Half laminar and turbulent model trying to sol
 
I have now used the command:

define/boundary-conditions/fluid

however there is no sign of a command prompt for deciding laminar or turbulent...

Is this because im not using the new ansys/fluent program or is it possible with 6.3 fluent?

Andrew Clarke May 19, 2008 13:40

Re: Half laminar and turbulent model trying to sol
 
Ah yes.. got it. I must define the viscous solver overall as turbulent and then the option appears in the command prompt. Many thanks for your direction in help. May the pressure*area be with you...


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