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turbulent dissipation rate of e B.C.

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Old   July 18, 2013, 05:48
Default turbulent dissipation rate of e B.C.
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C.C
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Hi all,

I'm trying implement a low-Re turbulence model using an UDF in Fluent. I know that I can turn on the low-Re turbulence model in Fluent, but the main objective is modify one of the models by changing the damping functions.
The model that i'm using have a boundary condition for epsilon as:
\epsilon_wall=dynamicviscosity*∂^{2}k/∂^{2}y (expression in attached file)
but there is no command for the second derivative of k.
Anyone can help me... How can I implement this boundary condition in a UDF?
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Old   July 18, 2013, 12:27
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Another question: what is the better way to change the boundary condition at wall for epsilon (expression as a function of second derivative of k)? It is going to Boundary Conditions->Wall.1->Edit->UDS Boundary condition and in User-Defined Scalar Boundary Value changhe for the variable name defined in the UDF?
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