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Old   January 24, 2013, 18:56
Question Skin friction coefficient
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Meimei Wang
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Hi,

I'm looking for the skin friction coefficient formula that CFX uses. But I didn't find it on user manual.

Could you please tell me which skin friction coefficient formula does CFX use?

Thank you very much!
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Old   January 25, 2013, 11:51
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tau_wall/(1/2*rho*Uinf^2)?

Not sure what you mean. Do you mean how do they get tau_wall?
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Old   January 25, 2013, 19:08
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Quote:
Originally Posted by singer1812 View Post
tau_wall/(1/2*rho*Uinf^2)?

Not sure what you mean. Do you mean how do they get tau_wall?
Yes. I guess it compute tau_wall by this

http://www.cfd-online.com/Wiki/Wall_shear_stress

But does it just set the fluid velocity at the wall as 0 then compute the (du/dy)_{y=0}? But how does it know du/dy at the wall(y=0) without knowing the wall shear stress in advance?
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Old   January 28, 2013, 10:25
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That can be a complicated discussion. I suggest looking at chapter 2 of the CFX Theory Guide.
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