Boundary Layer Development and Spillway Energy Losses

Recent studies of the mechanics of the turbulent boundary layer development have resulted in knowledge applicable to the spillway energy loss problem. The significance of the boundary layer, displacement, momentum, and energy thicknesses is studied relative to the spillway energy losses. The results of a laboratory investigation on the turbulent boundary layer development are correlated with limited prototype data and extended to include the concept of energy thickness. A design procedure is included that should provide more accurate estimates of spillway energy losses than procedures previously published. Design charts are also included. In most cases of high structures the turbulent boundary is probably not fully developed before the design flow reaches the energy dissipators. Therefore, the described procedure should serve as a useful design tool.