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-   -   Recommended values on turbulence B.C. (http://www.cfd-online.com/Forums/cd-adapco/54788-recommended-values-turbulence-b-c.html)

Jihwan August 9, 2005 00:48

Recommended values on turbulence B.C.
 
Hi there,

I am not good at turbulence. But, as you know, it is very important to consider turbulence for the flow in complicated geometries. What I want to know is that whether there are good recommendations for the turbulence boundary conditions. Of course, the turbulence B.C. should depend on flow pass and environments. I hope to get any literature concerning recommended turbulence boundary conditions for various flow conditions and geometry. Thanks in advance and good luck everybody

Jihwan

AlexMuthaiah August 10, 2005 03:53

Re: Recommended values on turbulence B.C.
 
Hi, Turbulence Boundary condition in the sense u need to maintain a suitable Y+ values around the wall region and which inturn depend on ur tubulence models which u r going to use. For each TModels appropriate closure coefficients u need to use usually software will take care by using its default values.

U need to check for gridsenstivity.

regards'

Alex

allan August 10, 2005 07:45

Re: Recommended values on turbulence B.C.
 
Hi

If you are considering inlet boundaries then you could try setting turbulence intensity to say 2%, running the model then double it and run the model again and so on until there isn't any appreciable difference in the turbulent flow field.

For internal flows length scale can be set to 10% of the hydraulic diameter of the duct.

Y+ is also very important, but if you choose hybrid wall functions then it becomes less of an issue.

allan



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