Numerical Simulation of Long-Distance Diversion Tunnel with Free Flow Based on the VOF Method

The 3D standard k-epsiv model of water-air two-phase flow coupled with volume of fluid (VOF) method is established in long-distance diversion tunnel with free flow. Considering the wall roughness, the method of wall functions is adopted near the walls. The results show that the disturbance zone of water flow appears at the inlet. The mutation zone of water flow and air flow vortex appear at the outlet. Water flow vortex appears at the intersection of main tunnel and branch tunnel. The calculated results are compared with the water depth data measured in the drainage and emptying tunnel of a reservoir, indicating that the simulation results agree well with experimental ones.