黄河小浪底库区高含沙异重流的运动过程分析

Analysis on character of hyper-concentration density flow in Xiaolangdi Reservoir in the Yellow River

从黄河小浪底水库实测资料出发,描述了水库异重流厚度、流速、含沙量随时间的变化过程,其沿程变化受地形的改变和进出库水沙量的影响;分析了水库异重流潜入的运动特性及异重流运行过程.结果表明,各断面异重流厚度随时间表现为发生、增强、维持和消失4个阶段;异重流的厚度、流速和含沙量除受制于地形外,还受制于进出库的水量;异重流潜入点附近水流的Fr数与范家骅公式计算值基本一致,异重流潜入点随库水位的下降而下移,随来水来沙的增大而下移.

Based on analyzing the observation data of the Xiaolangdi Reservoir in the Yellow River, this paper presents the depth, the velocity, and the sediment concentration change with time which is affected by topographic and water flux. Results indicate that the depth of density flow varies by four stages with time, i.e. appearance, swell, maintaining and disappearance. The depth, the velocity, and the sediment concentration of the density flow are affected by not only topographic change but also water flux into or out of the reservoir. It is indicated that Fr in the section where density flow plunges into the bottom of the reservoir in the paper is basically consistent with Fangjiahua formula. The section where density flow plunges moves downward when the water level of reservoir descends or when incoming water and sediment increase.