Abstract
Riverbed is not so even. When fluid flows through the plane bed, sand ripples, sand dunes, anti-dunes will appear on it with the increase of the current intensity, which exist in the channel widely and determine the resistance of the bed, the movement of the sediment and so on. What kind of bed form would appear is mainly affected by the flow structure; on the contrary, the bed form also can affect the flow would structure. Aiming at this kind of condition, the instability characteristics of laminar flow in open channel is discussed in this paper, which has essential differences with that on plane bed. During the solving process, Floquet theory is used to analyze the problem and spectral collocation method, Muller method and QR method are adopted to calculate the model established. And finally some important conclusions are reached through the theoretic analyzing and the numerical calculating. This kind of study can set a foundation for the later theoretical researches on bed evolution in the lower reach of Yellow River near estuary and the interaction of riverbed and current.