Sand Waves に関する研究 ―Sand Waves の波高に関する一考察―

Abstract

Wave propagation in one-dimensional erodible bed channels is discussed by using thequari-steady approximation for shallow-water equation. This analysis starts from theasumption that sand waves of propagating without the variation of the from may exist.As the result of this analysis, an equation which decides the wave height of sand wavesfor low flow regime is obtained.This expression well explains qualitatively the actual phenomena as follows. In thecase of initiation of ripples with low Froude number, the wave height is very sinally bythe effect of the critical tractive force. In duine regime, that develops suitable scaleaccording to the flow condition. And in the case of transition, the wave height againdecreases by the effect of the critical Froude number.Numerical comparison of computed wave height and measured one shows goodagreement in dume regime. But in ripples, the former is larger than the later. Thiscause must be discussed by further studies.