钱塘江涌潮对风场响应的三维数值研究

台风作用下钱塘江涌潮观赏性强，破坏力大。结合台风期实测潮汐资料分析，基于三维数学模型研究了顺风和逆风条件下恒定风况对钱塘江涌潮水流的影响，得到了不同风况对涌潮高度、流速、传播速度和涌潮潮景的影响程度。顺风作用导致涌潮高度、流速和传播速度均增大，风速愈大，增加幅度愈大，涌潮流速沿水深分布愈不均匀。在顺风30 m/s风况下，盐官涌潮高度增加5%，涌潮流速增大33%，涌潮传播速度加快37%；顺风作用下，老盐仓回头潮更强，回头潮水位更高，反映了台风期间老盐仓经常出现回头潮翻越海堤堤顶的情况。逆风作用与顺风作用相反。计算结果与实际情况在定性上一致。

Three-dimensional numerical study on the Qiantang River tidal bore under winds

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.