Use the Friction Factor to Calculate Frictional Head Loss (Pressure Drop) for Pipe Flow

The Darcy Weisbach equation relates frictional head loss (or pressure drop) in pipe flow to the pipe diameter, pipe length, average flow velocity, pipe roughness, and Reynolds number. The Darcy Weisbach Equation can also be considered to be an equation giving frictional head loss (or pressure drop) as a function of the friction factor, pipe length/pipe diameter, and the velocity head, where the friction factor is a function of Reynolds Number and pipe roughness/pipe diameter. The Darcy Weisbach Equation can be used for pipe flow that is fully developed flow and turbulent flow. Turbulent flow occurs in pipe flow for Reynolds Number greater than 4000.