潮汐河口闸下风暴潮特征模拟

潮汐河口闸下风暴潮水位对于河道防洪排水至关重要。以苏北里下河主要入海通道射阳河、黄沙河、新洋河和斗龙河等建闸河口为例，采用模型嵌套的方法，以平面二维数学模型模拟了里下河地区“9711”台风风暴潮期间闸下河段的潮汐水流和风暴潮运动过程，研究了闸下风暴潮水位相对河口风暴潮水位的变化特征。模拟结果显示，底摩擦、浅水变形、边界反射等相互作用影响，闸下风暴潮水位和潮汐水位存在一致的变化特性，即高潮位抬升，低潮位下降，潮差(增水)增加；涨潮历时缩短，落潮历时延长；风暴潮水位的变化幅度大于同时期的潮汐水位，风暴潮过程对于闸下排水具有显著影响。在与闸顶高程一致的上游水位条件下，相比天文潮过程，“9711”风暴潮过程可减少闸门过流流量的20%~25%。

Numerical simulation of storm surge characteristics in downstream of tide sluice located at tidal estuary

Evaluation of the storm surge in the downstream of the tide sluice is vital to flood control and drainage from a tidal estuary. The Lixiahe district including the Sheyang River, the Huangsha River, the Xinyang River and the Doulong River situated at the north of Jiangsu Province are taken as a case study, and the tides and storm surge processes induced by "9711" typhoon are simulated by a 2D mathematic model with the nesting grids. And the storm surge characteristics of the downstream of the tide sluice are discussed, compared with those in the river mouth. The calculated results show that the storm surge vary in consistent with the tidal waves influenced by interaction of bottom friction, wave transformation in the shallow water and boundary reflections. In the downstream of the tide sluice, the high water level rises, the low water level falles, the tidal range (surges) increases, the rising tide duration is shortened, and the falling tide duration extended. And the variations of the storm surge are greater than those of tides. Furthermore, it is found that the storm surge has a significant influence on the drainage in the downstream of the tide sluice located at the estuary. The case study shows that when the water level in the upstream is as high as the sluice gate, the flood discharge of the sluice gate would decrease by 1/5 to 1/4 due to the "9711" storm surge.