# Turbulence Specification Method

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 March 16, 2005, 14:48 Turbulence Specification Method #1 Srivatsan V. Rajagopalan Guest   Posts: n/a 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

 March 17, 2005, 04:11 Re: Turbulence Specification Method #2 ROOZBEH Guest   Posts: n/a 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 palmerlee likes this.

 March 17, 2005, 11:49 Re: Turbulence Specification Method #3 Srivatsan V. Rajagopalan Guest   Posts: n/a 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!

 April 4, 2005, 00:50 Re: Turbulence Specification Method #4 mahmoud Guest   Posts: n/a

 May 20, 2009, 20:24 Hydraulic Diameter #5 New Member   mahadevan.swamy@gmail.com Join Date: Apr 2009 Posts: 15 Rep Power: 17 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

January 31, 2011, 06:39
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Quote:
 Originally Posted by mahadevan.swamy 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/