ABSTRACT
The hydraulic jump is the basic feature used to dissipate excess hydromechanical energy below a spillway. It corresponds to the most discontinuous and turbulent flow in an open channel. The main features of a hydraulic jump are its efficiency in energy dissipation, and its stability under varied boundary conditions. Because jumps in channels of non-rectangular cross section are prone to spatial instability, they are rarely applied in dam hydraulics. Stilling basins are popular and among the designer’s favorite choice for energy dissipation, certainly because of knowledge and experience acquired over the years. They have proved to be a reliable hydraulic structure if the approach flow conditions and the tailwater elevation are within certain limits. Drop structures are used if the tailwater required for a stilling basin is not available. Among various types of spillway outlet or transport structures, the free fall, spillway chute, and spillway cascade are the most prominent.
