Hydraulic Characteristics of Fishways Using a Fully Three-Dimensional Non-hydrostatic Pressure Mathematical Model

An accurate simulation of the three-dimensional (3D) flow structure of a fishway is performed. The simulation is based on an in-depth study of the advantages and disadvantages of the hydrodynamic characteristics of the fishway using a 3D mathematical flow and turbulence model. Triangular and quadrilateral hybrid grids are used to discretize the plane calculation domain and improve the adaptability of the mathematical model for complex boundaries. The vertical adaptive capture method is introduced to ensure that the zero-pressure boundary condition of the free surface can be accurately applied to the model. By solving the Navier–Stokes and turbulence closure equations, a high-resolution numerical solution format for the hydraulic factor of the fishway is developed. Thus, a fully refined 3D non-hydrostatic mathematical model for the hydraulic factor of a fishway in an inland river hub is established. The model can simulate 3D flow problems with high accuracy and efficiency. It has good adaptability to incorporate complex boundaries and can accurately simulate the 3D hydraulic characteristics of fishways with a free surface.