The Numerical Simulation for Effects of Y-Shape Flaring Gate Pier Body Type on Aerated Cavity Length and Negative Pressure of Steps

Abstract

Numerical simulation technology has been widely used to study the energy dissipation problem of hydroelectric engineering construction which combined flaring gate pier with stepped spillway. The main parameter of flaring gate pier is contraction ratio. This paper numerically simulated the length of aerated cavity and negative pressure of steps for stepped spillway combined with symmetrical Y-shape flaring gate pier which with the contraction ratio respectively of 0.4, 0.7 and 0.445. The RNG turbulence model ,VOF model of water vapor two-phase and iterative solution of geometry reconstruction format for unsteady flow has been applied to generate free surface. Velocity and pressure coupling method using PISO algorithm, with unsteady flow algorithm approaches stable solution of steady flow. And range from the upstream reservoir to downstream stilling basin. Comparatively analyze the experimental and simulation results of aeration cavity length, the two are basically in good agreement, and the maximum error is 10%. Therefore, the numerical simulation has a certain rationality and reliability. Simulation results show that aeration cavity length increased with the contraction ratio decreases, while the maximum negative pressure decreased, and more extensive distribution of negative pressure in stepped spillway.