河床波上の流れの三次元構造

Abstract

Techniques of flow visualization are used to make clear the three dimensional structureof the flow over ripples. Sterographs of the flow over ripples, pictures of the flow in thelongitudinal cross-sections and pictures of the flow patterns on the water surface are obtainedby using the moving cameras or the fixed cameras.For the flow over ripples, the slant spiral flow which occurs in the rear side of ripplesplays an important role in sediment transport. So, in this paper, attention is payed on themovement of the slant spiral flows in examinning the structure of the flow over ripples.On the basis of the data and the pictures obtained, the model on the three dimensionalstucture of the flow over ripples are proposed, in which the relation among a slant spiral flow, an upflow, a down flow, a secondary flow and bed configulations is made clear.