浮遊砂に関する研究(3) ―微細粒子の影響について―

Abstract

It is very important to understand the effect of wash load on sediment transportation andflow properties. In order to clarify the effect, the experiment for fall velocity in the still fluid insuspension of fine sediment and the experiment for concentration distribution of coarse sand inthe flow with fine sediment were carried out. It was clarified from these expermints that in thefluid in suspending fine sediment, relative viscosities increase and relative fall velcities decrease, with increasing the concentration of fine sediment. The concentration gradient of coarse sandin the flow with fine sediment decrease under the constant condition of shear velocity with the in-crease of the concentration of fine sediment.This paper showed that this phenomenon can be explained if we consider the changes ofthe viscosities with the increase of the concentration of fine sediment. Moreover, the increase ofthe wash load plays an role to increase the rate of suspended load.