New experiments were conducted in a large stepped channel with a 22 degree slope operating at large Reynolds numbers. Interactions between free-surface and cavity recirculation were systematically investigated in the skimming flow regime. Turbulence manipulation was further conducted and identical experiments were performed with 4 configurations. Basic results demonstrated a strong influence of cavity vanes (longitudinal ribs) on the air-water flow properties in both free-stream and cavity flows. The air-water flow structure (bubble and droplet size distributions, clustering factor) was significantly affected by the presence of vanes, and greater spray production was observed with the vanes. Air-water velocity and turbulence distributions highlighted further a major impact of the vanes on the entire flow
