Abstract:
The tidal bore is a kind of nonlinear strong discontinuous flow that has great impact on wading structures. The small-scale fine simulation of the tidal bore is the premise for analyzing the structural stability of the wading structures under tidal action. The large eddy simulation technique (LES) is used to solve Navier-Stokes (N-S) equations, and the volume of fluid (VOF) is selected to track the free water surface, and the boundary condition is determined by the tidal theory based on the tidal velocity and water depth conditions. The research results show that the tidal bore propagation velocity obtained by numerical simulation is close to the theoretical values. When
Fr < 1.3, the tidal bore is undular and is characterized by a marked roller when
Fr>1.5. The zoning of tidal bore morphology is consistent with the previous experimental results. During the tidal bore propagation process, the flow velocity at the tidal head is the largest, and the fluctuation of the surface velocities is always greater than the fluctuation of the velocity in the middle and lower layers. The lateral motion of the breaking bore head is stronger than the undular tidal bore. The simulation results also indicate that the water depth before the tidal bore and the height of the tidal bore are the main factors affecting the fluctuation and shape of the tidal head velocity. The simulation method of the tidal bore provides technical support for structural design and safety assessment of the wading structures in the tidal bore reach.