可視化法による大スケール乱れに関する研究 (2)-路床形態と大規模乱流構造との関連について-

Abstract

Experimental studies are made about large scale structure of turbulent open channelflow with the aim that the results can be applicable for the practical use in river hydra-ulics. Flow patterns containing eddies on water surfaces and ones in crosssections arevisualized by the camera moving with equal velocity with the mean flow. Flow patternscontaining low speed streaks and bursts near the channel bed are also observed. Artificialroughness elements are arranged on the channel bed in order to regulate the flow structure.The results are used to compose the structual model of turbulent shear flow, by whichdevelopment of secondary vortices to secondary flow, formation of surface eddies andboils, and occurrence of bursts, sweeps and low speed streaks are explained reasonably.