水库异重流运行特性试验研究

Experimental Research on the Movement Characteristics of Reservoir Density Currents

采用物理模型对水库异重流运行的距离和运行速度进行试验研究,在此基础上,通过对异重流微小控制体进行能量守恒分析,建立了异重流头部运行速度计算公式,并进行参数率定。研究结果表明,水库库区异重流发生的时机多为汛期的初次不连续洪水期,入库含沙浓度越高、流量越大,异重流运行距离越长,只要洪峰时间足够长,浑水不断补给,异重流运行到坝前的可能性就大,反之,异重流难以运行到坝前;异重流头部运行速度与河床比降、异重流厚度、浑水容重等因素密切相关,文中建立的公式能较好反应水库异重流的头部运行规律,可为水库异重流的研究提供参考。

Density current moving velocity and the farthest moving distance are studied by physical experiments in this paper. And based on an energy conservation analysis of reservoir density currents, a formula about the speed of reservoir density currents is constructed. The experiment results indicate that the density currents usually occur in the flood season. The sediment concentration of discharge and the riverbed gradients are the important factors leading to density currents. The density flow can move to the front of dams if the flood time is long enough. Otherwise, the density currents can not be formed and not arrive at the front of dams. The moving velocity of density currents has a close relationship with riverbed gradients, the depth of density currents and the sediment concentration. The formula established in this paper can better reflect the moving rules of reservoir density currents, and can serve as a reference for reservoir density current research.