Velocity Distribution of Turbulent Flow in a Pipe

In case of turbulent flow Reynolds found that the loss in pressure head is proportional to V n where V is mean velocity and n varies from 1.75 to 20. Transition from laminar to turbulent flow depend upon pipe diameter and the physical properties of the fluid also. • The factors which affect the transition from laminar to turbulent flow are: 1. Turbulence prevailing in the incoming fluid. 2. The pressure gradient: For accelerated flow critical Reynolds number increases whereas for retarded flow , critical Reynolds number decreases. 3. The roughness of boundary decrease the critical Reynolds number. • Below a critical Reynolds number all disturbances are suppressed by viscous damping while above the critical Reynolds number certain frequencies will be amplified and others damped. • According to Darcy-Weisbach equation, the loss of head due to friction in the pipe is given by hf = where f = Friction factor L = Length of pipe V = Mean velocity of liquid D = Diameter of pipe • Major loss of...