根据黄河下游河道特性分析,统计了河湾平面、断面几何参数,确定了典型游荡型河弯;根据黄河下游洪水特性分析,确定了四种典型水流条件与槽滩分流比。为研究新型板桩潜坝导流功效与局部冲刷问题,进行了针对性的动床模型设计。分析确定了满足水流泥沙运动相似与河床变形相似的控制比尺,选择的模型沙及其粒径能够满足起动相似条件。模型设计采用了槽滩分流的进流控制模式、滩地加糙模式,同时采用VDMS流场实时监测系统进行流态与导流效果的观测,以便正确模拟研究河段特点及新型整治工程作用。
By analysis of the geometric parameters of plan-form and cross-sections of the Lower Yellow River,the typical wandering river bend was determined.Four typical flow conditions and the ratio of discharges of the principal channel and floodplains were also determined according to the characteristics of floods of the Yellow River.A movable bed model test was carried out to study the flow diversion efficiency and local scour of a new-type submerged spur of sheet piles.The model scales were selected based on the principal of similarity of water flow and sediment movement.The model sediment was selected to fulfill the condition of similarity of incipient motion of sediments.To simulate and study the characteristics of river reach,the model was designed with separate inflows of the principal channel and the floodplain and the floodplain was artificially roughened.Meanwhile,the VDMS flow field monitor system was used to observe the flow state and the effect of river regulation works.