Abstract
The flow over a stepped channel can be divided into two regimes: nappe flow and skimming flow. It is indicated that for a nappe flow regime the energy dissipation occurs by jet breakup in air, by jet mixing on the step and that for skimming flow regime the energy dissipation is enhanced by the momentum transfer from main flow to skimming fluid near the steps. However, for the stepped steep channel where the wake vortices do not fill the entire cavity between the edges of adjacent steps, the flow structure was not clarified yet. In this study, the skimming flow characteristics in a stepped open-channel was discussed on the basis of experimental data of main flow velocity, pressure on channel bed and water depth. The authors found the correlation among them along the downstream distance from the step edge and clarified the three-dimensional flow structure embedded in the skimming flow from their spanwise variation.
