蛇行流路の形成過程に関する研究

Abstract

In addition to the previous experiments of stream channel process, the results of two experi-ments which have been conducted by the use of the stream channels with different initial bankheight are reported. One of them forms a braided channel because of steep bed slope caused byimmediate collaspe of side bank in the beginning of experiment. The condition of meanderingchannel formation and the characteristics of the bars in channels with bank erosion is examinedby the application of BI/R-U*/U*c criteria.The hydraulic analysis of the process of channel meandering is developed, considering thatmeandering bends progress by the concentration of discharge in main stream which is formedbetween front of bar and outer bank line. In this analysis, orthogonal curvilinear co-ordinatesare taken along the center line of main stream on the initial bed plane and in-flow to main streamfrom upstream side bar and out-flow from main stream on downstream side bar are considered, and outer bank erosion rate is assumed to be in proportion to depth and to third power ofvelocity. The computational procedure are very complicated and several assumptions areintroduced. The analytical results show the characteristics of meander development andagree with the results of experiment.