Average Temperature in a Cylinder
 

I want to know how can I get the average temperature of a hall cylinder (3D) that is rotating at a constant velocity.

I took constant temperature at the outer surface ( walls ) as a boundary conditions T wall = 1 degree and T i = 25 degree.

NB: Hall cylinder means: avg temperature of the inner volume of the cylinder plus the outer surface (Cylinder walls that are always equal to T cte = T wall).

Thanks a lot.

Without going into the exact details of your problem, you may use the definition of average: f_avg = 1/V* Integral on V of f*dV for volume average, and similarly for averages of surface, line, time etc.