複断面蛇行流の可視化観測

Abstract

The horizontal cross-sections of the meandering channel flow with compoundcross-section were visualized using fine particles as tracers. Picture films weredigitized and processed by the computer to obtain two-dimensional distributions ofvelocity vectors.The flow structures on the flood plain were shown to be composed of the zoneof a large scale separation vortex motion and the zone of longitudinal vortexmotions. The flow structures in the lower part of the deeper river course arecharacterized by the longitudinal vortex motions with the scale of the deeper coursedepth.The flow structure of particular interest is the separation vortices occurring inthe interacting region between flood plain flow and deeper course flow. The three-dimensional structures of these vortices were elucidated and possibility for thesevortices to appear in flood conditions was discussed.