【摘要】 本文应用有限差分隐式格式和追赶法同步求解水流运动方程和河床冲淤变形方程,进行水库冲淤发展过程计算。这种方法在物理图形上,比之国内目前多数采用的有限差分显式格式,即水面线与河床变形交替计算的方法,更能同时反映水力因素与河床变化相互影响相互制约的关系。在数值计算求解方程上,它也比显式差分格式具有稳定性好、允许时间步长较大、运算速度较快的优点。文中以国内习惯采用的武汉水利电力学院挟沙力公式形式作为补充方程,进行了一维等宽恒定非均匀流条件的溯源冲刷计算,以三门峡水库实测资料进行了验证。说明只要选取合适的参数,可以得到符合实际的计算结果。此外,对淤积后床沙细化所引起的糙率减小和挟沙力系数改变作些简化处理,进行一维条件的壅水淤积计算,结果可反映水库悬沙淤积平衡比降小于原河床比降的物理现象,这种现象为许多水库实测资料所证实。更多还原

【Abstract】 By using the method of finite differences of implicit scheme and double sweep method, the basic equations of motion of unidimensional steady flow and river bed deformation for predicting the water level and river bed variation due to aggradation and degradation of suspended load in a reservoir are solved numerically. The suspended load transport formula of Wuhan Institute of Hydraulic and Electric Engineering is applied. As the bed composition after sediment deposition becomes finer than the original bed composition, modifications of roughness coefficient and sediment transport coefficient are considered. Thus the results of computation of longitudinal profile can reflect the natural phenomena more accurately.Then, this method is used to calculate the headward erosion due to water level lowering in the Sanmenxia Reservoir. The results of theoretical calculation agree well with the field measured data. Besides, this method can also be used to predict the aggradation of an impounding reservoir with channel cross section.更多还原