Tube Flow (- du(r) shear dr shear rate stress profile profile u(r） parabolic velocity profile The physical parameters relating to flow in a tube:flow rate pressure drop P along the pipe of length L and radius a.Newtonian Fluids gú w = 4Q pa 3  w = Pa 2L    gú = Ppa 4 8LQ gú w and s w are values or shear rate and stress at the wall of the tube. At the center of the tube : gú o and s o = 0 Tube Flow u(r) = P 4hL a 2 - r 2 ( )