二维非恒定流数学模型在赣江河流治导线研究中的应用

Application of a two-dimensional unsteady flow model in research of regulation line of Gan River

为了给赣江河流治导线研究提供科学的决策依据,以赣江吉安水文站至峡江坝址河段为例,采用二维非恒定流数学模型研究了河道洪水特性,获得研究区域内全河段水位、水深、流场和水流动力轴线等信息,根据不同时刻的二维模型计算结果得到洪水淹没范围,并结合河湾形态及水流动力轴线弯曲半径确定了迎流顶冲河段。研究结果表明:计算河段的水位变幅沿河道总体趋势从上游至下游逐渐增大,下游峡江坝址附近水位变幅约为2 m,上游吉安水文站处水位变幅约1.4 m,各断面洪峰流量从上游至下游依次出现,上、下游最大流量出现时间相差约10 h;受河道两岸圩堤、山体、高地等条件控制,洪水基本被约束在河道内,部分低洼、平坦地区洪水淹没范围较广。依据研究结果,在研究区域内确定了7处迎流顶冲段的位置和范围。

In order to provide a scientific basis for the study on regulation line of Gan River, taken the reach from Ji＇ an hydrology station in the upstream of Gan River to dam site of Xia River as an example, flood characteristics including water level, water depth, flow field, and flow hydrodynamic axis were studied by using a two-dimensional unsteady flow model. The flood submerged range was gained from calculation results by this model, and then the river band scoured reaches were determined through the river band morphology and the bending radius of flow hydrodynamic axis. Research results show that： water-level variations of the study reach gradually increases from upstream to downstream, the water-level variations near the dam site of Xia River is about 2 m, and the water-level variations of the Ji＇ an hydrology station is about 1.4 m. The peak flow of each section sequentially appears from upstream to downstream, and the time for the maximum peak flow occurring between upstream and downstream is 10 h. Restricted by both sides of riverbank, massif, and highland, the flood of the reach is almost retrained in the watercourse, and the flood submerged range is relatively board in some flat low-lying region. According to the above research results, the position and range of the seven river band scoured reaches were determined.