安康枢纽回水变动区航道整治数学模型研究

安康枢纽回水变动区河段的通航水流条件既受上游石泉枢纽日调节影响,又受下游安康枢纽水库调度的影响。河道水流既有山区河流滩险水流特性,又有库区河道水流特点。同时,该河段为连续急流弯道段,研究难度大。文中采用平面二维水流数学模型的技术手段,研究回水变动区河段滩险整治工程方案。针对天然河道边界复杂等特点,研究采用正交贴体网格。在此基础上建立了平面二维水流数学模型。采用有限体积法对平面二维水流控制方程进行了离散。对安康枢纽回水变动区天然情况下的水位、比降及水流流速等进行了验证计算及分析,验证结果表明,所采用的数学模型和计算方法能够准确模拟枢纽回水变动区的水流运动特性。根据河段的河道特性、河床演变特点及碍航特点,提出了航道整治原则。在上述整治原则的基础上,对安康枢纽回水变动区河段滩险整治方案效果进行了计算分析,并提出了能够达到设计航道尺度的整治工程方案。

Study on mathematic modeling of channel regulation in fluctuating backwater zone of Ankang hydro-junction

The navigation flow conditions in fluctuating backwater zone of Ankang hydro-junction not only are influenced by daily regulation flow of Shiquan hydro-junction upstream,but also are influenced by reservoir operation of lower Ankang hydro-junction.The flow in fluctuating backwater zone is characterized not only with the characteristics of mountainous river,but also with the characteristics of reservoir area.At the same time,the reach is a continuous rush curve reach.This paper presents a study of two-dimensional modeling for fluctuating backwater zone of Ankang hydro-junction,following a sustained research program.A depth-averaged two-dimensional mathematical model is established under the orthogonal curvilinear body-fitted coordinate system with staggered grid.The governing equations of flow are discretized with the finite volume method.The computed water level,velocity are verified by field data in the fluctuating backwater zone of Ankang hydro-junction.It is shown that the flow field in fluctuating backwater zone can be simulated reasonably well.According to the characters of the fluvial process and navigation-obstruction,the regulation method is presented.Based on the aforementioned regulation method,variations of water level,surface slope and flow velocity,caused by the regulation works in fluctuating backwater zone of Ankang hydro-junction are analyzed.And finally,the reasonable regulation works are proposed.