chapter  Chapter 5
83 Pages

Energy dissipation

WithGeraldo Magela Pereira

Energy dissipators are classified according to the following concepts: those in which the dissipation occurs through the hydraulic jump and the stilling basins, for small to medium heads up to 30 m; those in which dissipation occurs in a slope chute, for heads larger than 50 m; and those in which dissipation occurs in steps. In heterogeneous masses and where there is low resistance, lateral scour can rapidly develop asymmetrically and evolve toward the walls or the foot of the dam, as happened downstream of the service spillway of the Tarbela dam. To select and optimize the most effective spillway layout and associated tailwater dam, it was decided to build two models, one in France and one in South Africa. Foundation conditions influenced the design of both the spillway and the plunge pool. A hydraulic jump will form when a supercritical flow with small water height strikes a body of water with a considerable height and subcritical velocity.