采用特征线理论对滚波演化的多重时间尺度进行分析,结果表明坡降较大的滚波演化数值模拟必须采用水沙耦合模型;由于含沙量变化的时间尺度慢于水流变化的时间尺度,含沙量不能很快地调整到水流挟沙力,因此滚波演化必须采用非饱和输沙模型;冲淤厚度、含沙量等因素对滚波结构的影响很小,床面形态是影响滚波水动力学特性的主要因素.
Roll waves are such series of shallow water waves that develop spontaneously in an overland flow when the flow surface is not flat and its longitudinal profile undulates periodically.Using multiple time scales of the roll waves,it can tell that how the bed deformation affects the flow.On this basis,the applicability region of mathematical river models can be delimited.Numerical simulations are made to illustrate the development and propagation of roll waves over mobile bed;the results of which indicate that the morphological evolution of the bed influences dynamic characteristics of roll waves greatly.