The dissolved oxygen concentration in a flow changes with distance downstream of the spillway crest and depends on the geometric configuration of the spillway and the hydraulic and operating conditions. A mathematical model was developed to simulate the turbulent structure of the flow over the spillway of the Three Gorges Dam at the 145 m reservoir water level to study the aeration characteristics and the gas transport. The model was calibrated and verified with measured data. The analysis of distribution of the aeration and the dissolved oxygen showed that the downstream water level, upstream dissolved oxygen content, and the flow discharge all affect the dissolved oxygen saturation downstream of the sluicing dam. The simulation provides guidance for controlling the dissolved oxygen supersaturation and environmentally friendly operation of the Three Gorges Dam.

In this study, a zonal grid refinement method based on the solution of weakly compressible flow equations with large eddy simulation in the finite volume method (FVM) and dynamic subgrid-scale model framework was used to simulate the turbulence structures of a plane-wall flow with Reynolds number Re=U₀δ/ν=10000. Comparison and analysis were conducted on the distributions of time-averaged velocity and velocity fluctuations, as well as on the actual near-wall structures, to verify the accuracy of the turbulence features that were simulated using the zonal grid refinement method. The results show that the zonal embedded grid is a very efficient way to illustrate the turbulence structures of the near-wall region. The present method is easy to implement and extend to small Mach number flow modeling on a collocated irregular FVM mesh system.