Turbulence Specification Method
 

I am using a K-Epsilon turbulence modelling for simulatig a supersonic compreeible turbulent flow in a nozzle. Can anyone pls tell me what to specify in "Turbulence Specification Method" in the "inlet panel" of Boundary conditions?

The Help in Fluent uses a "Intensity and Hydraulic Diameter" Can any one explaain me why it is so?

Srivatsan

Re: Turbulence Specification Method
 

Hi; You must set values as boundary condition for turbulence model equations, for example "k and e equations". You should set a value for k and a value for epsilon. But it is very difficult for a user to know what value is better to set. Instead, you can set values for turbulence intensity and viscosity ratio or hydrolic diameter. Fluent uses these values for boundary conditions. ROOZBEH

Re: Turbulence Specification Method
 

HI Roozbez! Thanks for your suggstion. As mentioned by U, I use only Hydraulic diameter. Can U pls take a little time in eplaining me how to define Viscosity ratio? It depends on what? Thnk you in advance!

Re: Turbulence Specification Method
 

Hydraulic Diameter
 

Hi,

I am making a 2D case analysis by have a 2D body in a tunnel (plane). I don't know how to find the hydraulic diameter or the length scale of this problem. I do know that the air will be travelling at 27.76 m/s around the body. How do I calculate the hydraulic diameter for this 2D case? Any ideas? Thanks in advance

Swamy

please refer to this website. http://support.esi-cfd.com/esi-users/turb_parameters/