First of all, we would like to thank very much Guilhem "Piou-Piou" Chanteperdrix (mfn04 99/00), who helped us to find how to draw the following charts.
 
 

Results
Ther following results are obtained for a velocity of the inner circle of 1 rpm. The fluid use is "modified" water, that is to say that the viscosity is set to 0.1 rather than 0.001, to make the calculus converge.
The same results are plotted further down.

Representation of the velocity magnitude


 

A cut at an angle of 0 degree.