长江下游黑沙洲水道水流特性数值模拟研究

Research on numerical simulation of water flow characteristics in Heishazhou waterway of Yangtze River

黑沙洲水道为长江下游典型鹅头型分汊河道,2007年实施了黑沙洲水道航道整治一期工程,对其天然洲头部、南水道左槽、南水道心滩中下部等关键部位实施了守护,初步稳定了滩槽格局,改善了航道条件。但南水道心滩低矮,滩体束流作用不强,遇大水年航槽淤积,造成枯水期易出浅碍航。采用数学模型计算了不同流量下滩脊线加高、岸线崩退、左槽封堵3种工况的水流变化,并将其与天然情况进行对比,分析了出浅碍航的主要原因,提出了应对措施,可为二期工程方案的设计提供参考。

Heishazhou waterway is a typical goose-head pattern braided channel in the lower reaches of Yangtze River.A series of engineering measures were taken in2007to protect critical area of the Heishazhou sand bar,including the head of sandbank,left channel and sandbank of South waterway.These measures preliminarily help stabilize the sandbank-groove pattern and improve the channel capacity.Due to the low elevation of channel bar in South waterway and weak fluid constraints of the sandbank,navigation could easily get impeded during flood years.Using mathematical model,water flow variations were calculated under three working conditions including heightened crest line,river bank failure and blocked left channel,and the results were then compared with water flow in natural state.Major reasons for navigation obstruction were found out and countermeasures were put forward,which provide reference for design of second-stage engineering scheme.