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-   -   User-defined turbulent viscosity - kinematic or dynamic? (http://www.cfd-online.com/Forums/main/67402-user-defined-turbulent-viscosity-kinematic-dynamic.html)

tstorm August 13, 2009 16:45

User-defined turbulent viscosity - kinematic or dynamic?
 
The k-e and k-w models have the option for a user-defined turbulent viscosity. Does anyone know if that turbulent viscosity is dynamic viscosity or kinematic viscosity? The difference of course is just a factor of density, which is nearly 1 for air in SI units, so the difference is small. Still, I don't know which it should be.

tstorm August 13, 2009 16:50

Sorry, this should have been in the FLUENT section. I'll repost it there.

aatman August 21, 2009 02:15

Quote:

Originally Posted by tstorm (Post 226277)
The k-e and k-w models have the option for a user-defined turbulent viscosity. Does anyone know if that turbulent viscosity is dynamic viscosity or kinematic viscosity? The difference of course is just a factor of density, which is nearly 1 for air in SI units, so the difference is small. Still, I don't know which it should be.

the question seems strange to me, kinematic and dynamic viscosity are a characteristic of the fluid, instead the turbulent viscosity is a characteristic of the flow, it is defined to close Navier Stokes equation with turbulence model

tstorm August 21, 2009 11:16

Yeah, I realized my mistake shortly after posting that thread. Thanks for your response though.

Yogini January 29, 2010 12:08

Hello,

Two equations models(k-e and k-w models) are used to find the eddy viscosity(or turbulent viscosity).And the turbulent viscosity is dynamic viscosity.


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