Flow regimes and energy loss on chutes with upward inclined steps

Abstract

This paper presents new experimental data on water flow on stepped chutes with upward inclined steps. The slopes of the chutes are 30°, 45°, and 60° whereas the upward angles of the inclined steps are 10°, 20°, and 30°, respectively. Classifications of flow patterns by empirical correlations are presented. Based on dimensional analysis, the important parameters are analyzed, and the relevant dimensionless parameters are established. The energy loss and outlet velocity are strongly influenced by the Drop number and the slope of the stepped chutes. As the Drop number increases, the energy loss ratio decreases. At identical Drop numbers the energy loss ratio on the more moderate slope is greater than on the steeper. The adverse slope of the inclined steps increases the energy loss ratio and decreases the outlet velocity by less than 10%. To estimate the kinetic energy ratio, an empirical equation is proposed.Key words: stepped chutes, inclined step, energy dissipation, skimming flow, spillways.