shear velocity
 

Hi everyone!

I've been trying to validate my CFD code but wasn't successfull. If you could help me out it would be very appreciated:

I want to model the flow field in an open channel and compare the velocity profile with the universal logarithm profile.

In order to calculate shear velocity I've used the equation: usatr=U/C*(g^0.5) in which C is the Chezy coefficient and U the mean channel velocity.

Now the problem is the numerical results don't match the logarithm profile. The question is: Is the method I use to compute shear vel wrong?
Right now I'm assuming that the viscosity is constant.

Thank's in advance for your help
Good luck