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-   -   Use of Tu for user expression (http://www.cfd-online.com/Forums/cfx/22926-use-tu-user-expression.html)

Adam August 7, 2006 07:55

Use of Tu for user expression
 
Has anyone successfully used the turbulence intenstity (Tu) in a user expression or subroutine?

Even though it is a user input option it doesn't seem possible for the user to utilise it in any expression or routine.

Regards

Adam

James Date August 8, 2006 03:21

Re: Use of Tu for user expression
 
Why don't you set it as a constant in the CEL expression language and then you can use it anywhere, even to set Tu on the inlet boundary. You could set up the following CEL expressions, which will allow you to calculate Tu and Epsilon:

UsrFlowSpeed = 10 [m s^-1]

UsrChord = 1.0 [m]

UsrDynamicViscosity = 0.0016 [kg m^-1 s^-1]

UsrDensity = 1028 [kg m^-3]

UsrTurbIntensity = 0.003

UsrInletK = 3.0*((UsrTurbIntensity^2)*UsrFlowSpeed^2)/2.0

UsrInletEpsilon = 0.085*UsrDensity*UsrInletK^2/ 10*UsrDynamicViscosity)

I hope this is useful.

James



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