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-   -   How to take Turbulent Intensity value for a SST-KW model (http://www.cfd-online.com/Forums/fluent/91477-how-take-turbulent-intensity-value-sst-kw-model.html)

mrdumpa August 12, 2011 00:14

How to take Turbulent Intensity value for a SST-KW model
 
Hello,
I have a question ie I am using turbulent model of SST KW model for my problem. But i have doubt which range we have to choose (value is 5 or 7 ). How to decide that value? Can anyone please help me to solve my problem..



Thanks in advance
Mahendra

husker August 16, 2011 12:06

Hi,

Turbulent intensity is guessed due to the problem. Details can be found in Fluent manual.

Examples:

Steady subsonic flow around airfoil at low angle of attacks, Intensity can be taken as 0.01 at the outlet. What if you take it 0.03? Nothing. It will have no effect.

Fully developed turbulent flow in a pipe or channel, Intensity can be taken as 0.1 at the inlet. If your pipe is very long, Intensity can be taken as 0.01 at the outlet.

Flow around circle? Intensity is supposed to be higher at the inlet and outlet than the two cases above, right?

As a result, please think about how much complex or turbulent your flow is.

mrdumpa August 17, 2011 13:46

Hi,
Thanks for your reply.
In my problem I took Turbulent intensity value is 5%. Actually i want to know how to take that value.

Reynolds number at inlet is 25000
i gone through Fluent user manual. From there i found the formulas is ......(rms velocity of fluctuating quantities /Avg velocity). Here I have a question .How to take fluctuating velocities value. If you have answer it is great


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