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-   -   SST turbulence with Gamma theta (http://www.cfd-online.com/Forums/cfx/119074-sst-turbulence-gamma-theta.html)

kmgraju June 9, 2013 10:46

SST turbulence with Gamma theta
 
Dear friends

How to model laminar - turbulent - laminar flow? .
Can I use SST with gamma theta model (default)?

Thank you

Far June 9, 2013 11:53

Yes you can use it.

kmgraju June 9, 2013 23:40

Quote:

Originally Posted by Far (Post 432932)
Yes you can use it.

Thank you for your kind reply.

My simulations has been finished .But at the end of the simulation , I found the following error message. Is this error message important?
+--------------------------------------------------------------------+
| ERROR #002100004 has occurred in subroutine Out_Scales_Flu. |
| Message: |
| The Reynolds number is outside of the range expected based on the |
| Option selected for the TURBULENCE MODEL. Check this setting, |
| the values of the properties, mesh scale, consistency of units |
| and solution values in the input file. Execution will proceed. |
+--------------------------------------------------------------------+

Thank you

Regards

Govind

Lance June 10, 2013 03:28

No, its only a warning. A forum search would have told you that.
See e.g. this post which came up when I searched for your error message:

http://www.cfd-online.com/Forums/cfx...tml#post431551

kmgraju June 10, 2013 11:13

Thank you Mr Lance

kmgraju June 18, 2013 12:34

Quote:

Originally Posted by kmgraju (Post 433124)
Thank you Mr Lance

Dear all
For low Re turbulence problem

for the first case, I use SST turbulence and not selecting gamma theta option then for the same boundary condition problem , I select SST turbulence and selecting Gamma theta option.

I got two different answers

Please guide me.

Thank you

Far June 18, 2013 13:25

Two different results of what parameter?

kmgraju June 19, 2013 10:14

Quote:

Originally Posted by Far (Post 434700)
Two different results of what parameter?

I have just created monitor points for pressure variation.
at the monitor points I have seen huge variation in two different settings

Thank you

Regards

wtkirk December 29, 2013 23:03

Quote:

Originally Posted by kmgraju (Post 434833)
I have just created monitor points for pressure variation.
at the monitor points I have seen huge variation in two different settings

Thank you

Regards

I would suspect that you are seeing pressure differences based on the nature of SST vs SST gamma-theta. The first model forces flow in the domain to be completely turbulent while the second model includes transition effects which means that the flow will be laminar for portions of the flow and will "naturally" transition to turbulent flow. Depending on the geometry and parameters of the flow the inclusion of transition effects can result in significant variations between the two solutions.

Hope this sheds some light on the issue.


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