Abstract:
Tidal bore in the Qiantang River attracts millions of people every year, especially under the action of typhoon, and also brings about a huge destructive power. Based on the analysis of field data on tide during typhoon, a three-dimensional numerical model is employed to investigate the effect of steady wind on the tidal bore flow in the Qiantang River. The variations of tidal bore height, velocity, propagation speed and the bore scenario are demonstrated. Tidal bore height, velocity and propagation speed increase under the favorable wind. The tidal bore is characterized by a larger increase under a stronger wind and the distribution of its flow velocity along water depth is remarkable. Under the favorable wind with a speed of 30 m/s, the tidal bore height and the velocity of the tidal bore flow increase by 5% and 33% respectively. Meanwhile, the propagation speed of tidal bore accelerates by 37%. Back-flow bore becomes more powerful and water level has a huge elevation, leading to the phenomenon that the back-flow bore overtops the seawall during typhoon. The power of tidal bores has a decrease under head wind. Numerical results are qualitatively consistent with the actual situation.