Abstract:Aiming at the issue that the strong impact force of tidal bores can cause significant sediment transport and bed deposition, thereby altering regional hydrodynamic characteristics, a small-scale refined numerical flume was constructed based on the OpenFOAM two-phase flow model.The propagation evolution and hydrodynamic characteristics of vortical tidal bores on varying topography were investigated, and the effects of bore height, pre-bore water depth, and topographic height on vortical tidal bores were analyzed.The results show that topographic uplift leads to drastic changes in the velocity and vorticity of the vortical tidal bore, and the bore energy significantly attenuates through vortex breaking and viscous dissipation. Weak vortical tidal bores degenerate into undular bores in shallow water, whereas strong vortical tidal bores maintain high-frequency oscillations due to concentrated energy. An increase in bore height reduces the attenuation of propagation velocity in shallow water and increases the turbulent kinetic energy of the surface water body. An increase in pre-bore water depth weakens the turbulent kinetic energy in shallow water and reduces the bore propagation velocity. An increase in topographic height slows down the propagation velocity of the vortical tidal bore. During propagation in shallow water, the turbulent kinetic energy decay rate of strong vortical tidal bores is significantly higher than that of weak vortical tidal bores. Based on the above numerical simulation results, a modified formula for bore propagation velocity that accounts for topographic uplift is proposed, and its calculated results are in good agreement with the numerical results, validating the accuracy of the formula.