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

hmd · October 13, 2010, 05:40

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, 08:27

$\mu$

Quote:

Originally Posted by hmd

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 $T_{ij} = 2\mu \times \frac {1}{2}\left(\frac {\partial{u_{i}}}{\partial{x_{j}}} + \frac {\partial{u_{j}}}{\partial{x_{i}}}\right)$

where i & j take valeus 1,2,3

to calculated Cf $cf = \frac {F_{x}}{\frac{1}{2} \times density \times U^{2}_{\infty}}$

October 13, 2010, 05:40	How to calculate viscous part of aerodynamic coefficients in 3D NS-flow	#1
hmd New Member jack Join Date: Oct 2010 Posts: 1 Rep Power: 0	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.

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