钱塘江涌潮影响因素分析

Analysis of the affecting factors on Qiantang tidal bore

应用二维浅水方程有限体积模型计算模拟钱塘江潮波在不同风况、上游径流、河床高程等条件下变化过程。计算结果显示:持续稳定10m/s的东风、东北风、东南风作用下钱塘江沿程测站呈"W"型增水过程,西风、西北风、西南风作用下沿程测站呈"M"型减水过程,七堡最大增/减水幅度大于2.2m/-2.1m;丰枯地形条件下,七堡站高潮位变化不大,但枯水地形低潮位抬高1.22m,相应潮差减小1.28m,和丰水地形比较,减小70%;上游大流量(2000m3/s)时,七堡站高、低潮位分别抬升了0.45m和0.89m,潮差减少0.44m。

A finite-volume model of 2-D shallow water equations is used to simulate and analyze the tidal bore in Qiantang River and different affecting factors are examined.The simulation shows that under a steady wind speed of 10m/s the surge takes W-shape if driven by east,northeast or southeast wind,while M-shape if driven by west,northwest or southwest wind,and that in these two cases the maximum surges at Qibao station are 2.2m and-2.1m,respectively.Under the small river volume of a dry year,the low water level at Qibao raises by 1.22m and the tide range is reduced by 1.28m.Under the river runoff of 2000m/s3 the high and low tide levels at Qibao raise by 0.45m and 0.89m,respectively,and the tide range is reduced by 0.44m.