1. The problem statement, all variables and given/known data For turbulent flow in a smooth, circular tube with a radius R, the velocity profile varies according to the following expression at a Reynolds number of about 10^5. Vx= Vxmax * [(R-r)/R)]^(1/7) where r is the radial distance from the center and Vmax the maximum velocity at the center. Derive equation relating the average velocity ( bulk velocity ) Vav to Vmax for an incompressible fluid. ( Hint: The integration can be simplified by substitution z for R-r ) 2. Relevant equations 3. The attempt at a solution i don't know which equation i should integrate and how?