河床形状・流れ・流砂量の非線形関係を考慮した交互砂州の平衡波高の理論

抄録

Alternate diagonal bars cause the increase in flow resistance and induced meandering flow over them forms a point of bank attack. It is, therefore, important subjects to investigate dynamic process leading to equilibrium bar height and to predict flow over alternate bars. The linear stability analysis provides a physical and mathematical explanation for occurrence conditions and evolutional process of alternate bar, but equilibrium bar height is not able to be determined because the bar increases in height with time. The present work made possible to estimate equilibrium height together with stabilization mechanism of alternate bars by considering non-linear relationship between bed profile and sediment discharge, which was divided into two non-linear relations of stream velocity versus bed profile and of sediment discharge versus stream velocity. Theoretical bar height coinsides fairly well with observed equilibrium bar height.