The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v = Velocity of the liquid in the pipe, μ = Viscosity of the liquid, and w = Specific weight of the flowing liquid)
32μvl/wd²
During the opening of a valve in a pipe line, the flow is
In axial flow fans and turbines, fluid enters and leaves as follows