ABSTRACT
During very large rainfall events, dams and weirs must be equipped with adequate flood release facilities for a safe dissipation of the kinetic energy of the flow. With stepped spillway design, it is essential to predict accurately the flow resistance associated with the steps. The authors investigate the flow resistance of skimming flows and associated form losses. New experiments were performed with channel slopes ranging from 5.7° up to 55°. The results provide a better understanding of the basic flow patterns and flow resistance mechanisms. They emphasise that form loss is dominant. Altogether more than 35 model studies and 4 prototype investigations (totalising more than 650 data) are re-analysed.
