Aeration performance of high-head siphon-shaft spillways by CFD models

Abstract Siphon-shaft spillways are constituted by covering above a shaft spillway with hood that creates siphonic pressure. This study focused on the aeration flow through aerator holes placed to prevent cavitational damage in high-head siphon-shaft spillways. Three-dimensional computational fluid dynamics (CFD) technique using finite-volume method solve Reynolds-averaged Navier–Stokes (RANS) equations for incompressible viscous and turbulent fluids motion was performed analyze full-scaled two-phase numerical models. The volume of (VOF) scheme used simulate (water–air) flow, defining fraction each throughout solution domain. accuracy model tested procedure recommended American Society Mechanical Engineers (ASME) CFD applications. results showed is highly effective reducing siphon sub-pressures cavitation. optimal relative diameter 0.45 provided sufficient air entrainment protect from cavitation did not decrease discharge performance too much.