ABSTRACT
Flow in open channels has been nature’s way of conveying water on the surface of the earth since the beginning of time. The following physical properties of fluids influence fluid motion, channel geometry, and help explain sediment transport. These are: mass; density; weight; specific weight; viscosity; shear; temperature; and elasticity and surface tension. There are several types of flow in open channels. These include laminar flow and turbulent flow; uniform flow and non-uniform flow; steady flow and unsteady flow; and tranquil flow, rapid flow, and ultra-rapid flow. Turbulence produces small velocity fluctuations at random in all directions with an average time value of zero. The hydraulic gradient in open-channel flow is the water surface. The energy gradient is above the hydraulic gradient a distance equal to the velocity head. The natural shape of an open channel may be markedly different from rectangles and trapezoids.
