Numerical investigation of air demand in free surface spillway tunnel

Abstract

During the normal operation of the spillway tunnel, the water velocity can reach 50m s-1. High-speed water flow leads to problems such as negative pressure and high-frequency noise above the tunnel, affecting the normal operation of various facilities in the tunnel and the health of the staff. In this study, a 3D numerical simulation of free surface spillway tunnel with a rectangular cross-section is carried out. The Euler multiphase model combined with the realizable k-epsilon dual turbulence equation was used to analyze velocity distribution of air above flow surface. The velocity distribution is maintained on the same curve with sufficient residual height. The calculation equation of air velocity distribution is fitted by the couette flow related theory, and the simulation results can be well predicted.