Abstract
The air-water flow properties of skimming flow over a moderately sloping stepped spillway with beveled-face steps were investigated using a non-hydrostatic depth-averaged mixture flow model. The proposed model couples the Boussinesq-type equations with the depth-averaged air transport equations. Additionally, it incorporates a depth-averaged k − ε turbulence model to deal with the turbulent issue of the self-aerated flow. The numerical solutions of these higher-order equations were obtained by means of a hybrid finite-volume and finite-difference scheme and were validated with a set of data from large-scale experiments. For the flow condition considered, the simulation results closely correlated with the experimental data, thereby demonstrating the model’s capacity for capturing the effects of air entrainment on the dynamic characteristics of the flow. Furthermore, the energy dissipation performance of the stepped spillway was examined. The results attested that the total energy loss decreases as the drop number increases, highlighting the link between the loss of the flow’s kinetic energy and the variation of the spillway discharge. With the established acceptable accuracy, the proposed model is well suited to analyzing the mean flow characteristics of aerated flow in such a type of stepped chute.