Author(s): K. Warren Frizell; Joseph P. Kubitschek; Jorge Matos
Keywords: No Keywords
Abstract: Stepped spillways operating in the skimming flow regime are well known to result in higher levels of energy dissipation than would occur on a smooth chute of equal drop. Empirical modeling and analytical methods using equivalent friction factors based on the step roughness have been successful in predicting general hydraulic characteristics such as depth and mean velocity. However, using bulk properties to design standard stilling basins has not always been successful, especially for stepped spillways of milder slopes. A review of previous research including new laboratory hydraulic modeling and computational fluid dynamics model data are used to gain insight to possible explanations which seem to infer that the mean energy available may not be as important as the chute slope and vertical distribution of energy entering the stilling basin. Factors such as air entrainment and stilling basin type are also considered.