ABSTRACT
Reliable information is available to predict head losses in conduit systems for which the geometry of the components in a system can be described in appropriate non-dimensional terms. This chapter presents loss coefficents that are based on components installed in isolation in a conduit system. In control structures, flow velocities and conduit passage sizes are such as to give flow Reynolds numbers well the transition from laminar to turbulent flow. Friction coefficients are dependent on Reynolds number, on relative roughness, k, and on cross-sectional shape. The long conduit before the component ensures a developed flow at inlet, and the long conduit at outlet from the component ensures that losses caused by flow re-development after the component are debited to the component. An allowance must be added to new conduit roughness values to account for deterioration in service brought about by surface deposits, erosion, bacterial slimes and growths, and corrosion.
