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-   -   Lift Coefficent - Advanced Model Control (https://www.cfd-online.com/Forums/cfx/23085-lift-coefficent-advanced-model-control.html)

Alex September 21, 2006 04:02

Lift Coefficent - Advanced Model Control
 
hey

I have a subsonic flow over a airfoil. My CL does not decrease by a high angle of attack. My Y+<2. Where can I set the crictical Re or where can I set a point for the flow to start changing from laminar to turbulent? In Turbulence Model - Advanced Model Control I can change many Coefficient (e.g. A1, k, BC, Beta Star, C) is there somewhere a help for these Coefficient, where I can see which Size and what happens when I change one. What else can I do? Thanks a lot for your help. Alex

Joe September 21, 2006 05:27

Re: Lift Coefficent - Advanced Model Control
 
Search the help file for the turbulence transition model.

Alex September 25, 2006 09:25

Re: Lift Coefficent - Advanced Model Control
 
thanks for the help. I decided to use the Gamma Model. the default value for the Transition Onset Reynold is 260. How do I calculate this value? I found:

Re_theta_c= 803,73*(Tu+0,6067)^-1,027*F(lamda,K)

F(lamda,k)= 1-(lamda*....)*e^Tu

Is this correct? How do I calculate Lamda(Pressure gradient parameter)?

Is it possible to calulate a critical Renoldsnumber via Re=x*u/v and enter this.

Thanks again


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