ON THE BEHAVIOUR OF ALTERNATE BARS UNDER SEVERAL KINDS OF CHANNEL CONDITIONS

The characteristics of alternate bars have been vigorously studied under steady flow conditions in straight and regular meander channels. However, in order to consider bed variation in actual rivers, it is important to clarify the bar deformation due to the changes in various channel conditions. Therefore, this paper deals with the behavior of alternate bars under several different channel conditions (e. g. the existence of a curved section and side-wall structures in a channel, and changes in the rate of sediment supply from the upstream) by means of experiments and numerical analyses. The changes of channel conditions leads to the different bar wavelength, bar height, and migration speed. Using the numerical results, the mechanisms of these phenomena are discussed.