非越流型水制群を有する開水路流れの水面振動と大規模渦の相互作用

Abstract

Spur dikes have been used to realign a channel or redirect main flow away from a streambank to protect it from erosive tractive forces. They are also used to increase channel roughness at locations that lack roughness elements. In certain cases, spur dikes can be used to narrow the channel in low-gradient, aggrading reaches causing flow velocities and sediment transport rates to increase. Water surface oscillation was produced in dikes fields when non-submerged spur dikes were set up in a case of their arrangements. The water surface oscillation was attributed to the interaction of large scale eddies formed in the spur dike fields along both banks, and was probably triggered by the separation eddies behind the first spur dike. This study focused on the interaction between water surface oscillation and large eddies in both cases of spur dike set up along both banks and one bank. The result showed that when a remarkable water surface oscillation was observed, the interaction of the large eddies in both banks was strong.