Abstract
We have tested the suitability of two non-linear analyses of the geometric and migration characteristics of alternate bars formed between rigid vertical walls of a straight channel. The development of alternate bars were predicted. The wave height obtained by an analytical method is higher than that obtained by a finite difference method (FDM). The difference is caused by higher wave number components in the simulated flow. The difference in the migration velocity between these analyses is large, which is caused by the difference of the bed geometry structure. It is found that the secondary flow which is estimated in the FDM by the stream line curvature affects the wave height very much. The wavelength of alternate bars produced by a bed disturbance located in the upstream end of the computational domain was found to be close to the wavelength obtained by a linear analysis.
