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-   -   How to calculate viscous part of aerodynamic coefficients in 3D NS-flow (http://www.cfd-online.com/Forums/main/80992-how-calculate-viscous-part-aerodynamic-coefficients-3d-ns-flow.html)

 hmd October 13, 2010 04:40

How to calculate viscous part of aerodynamic coefficients in 3D NS-flow

I appreciate if someone tell me how to callculate forces due to viscous stress tensor in 3D viscous external flow.
i mean:
Txx Txy Txz
Tyx Tyy Tyz
Tzx Tzy Tzz
I have writen a 3d navier-stokes code and want to calculate aerodynamic forces and CL ,CD, CM by viscous part . and how to calculate Cf, too.

Thanks alot.

 pavitran October 15, 2010 07:27

Quote:
 Originally Posted by hmd (Post 278952) I appreciate if someone tell me how to callculate forces due to viscous stress tensor in 3D viscous external flow. i mean: Txx Txy Txz Tyx Tyy Tyz Tzx Tzy Tzz I have writen a 3d navier-stokes code and want to calculate aerodynamic forces and CL ,CD, CM by viscous part . and how to calculate Cf, too. Thanks alot.
Hi,

you can find this in any advance fluid mechanics text book (Panton; White), but below is the general method to calculate Force contribution due to viscosity.

Fx = T11 x dAx + T12 x dAy + T13 x dAz
Fy = T21 x dAx + T22 x dAy + T23 x dAz
Fz = T31 x dAx + T32 x dAy + T33 x dAz

viscous stress is given as

where i & j take valeus 1,2,3

to calculated Cf

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