Faxen's 2nd Law: Learn How to Calculate Viscous Torque

[RobosaurusRex]

Can someone show me how Faxen's 2nd law for the viscous torque on a rotating sphere comes to be?

I know tau_(r phi) = -3 mu Omega sin(theta)

Torque is integral of vec(r) cross vec(f)

But I can't get the right answer so I am doing something very wrong

Help?

 

[jedishrfu]

This talk may help explain it better:

file://fileportal/redirect/Downloads/2_-_One_Sphere_in_Stokes_Flow.pdf