GENERATION AND DEVELOPMENT PROCESS OF COHERENT VORTICES IN DEPTH-VARYING UNSTEADY COMPOUND OPEN-CHANNEL FLOWS

Abstract

Database of unsteadiness characteristics of horizontal vortices in rectangular/compound open-channel flows is not yet available. Therefore, in this study, turbulence measurements were con ducted in the time -dependent and depth-varying unsteady compound open-channel flows using a PIV system. The generation and the development processes of horizontal vortices were investigated, considering the inflectional instability analysis. It was found experimentally that single eddy structure is changed to twin eddies structure as the increase of time-dependent depth.