Three-Dimensional Measurements of Turbulence in Biwako-Sosui Rivers

Abstract

One can say at present that the basic structure of open-channel turbulence has been almost revealed through experimental data of high quality using laser Doppler anemometers in laboratory flumes. However, these experiments have been conducted at moderate Reynolds numbers, say Re=10⁴. Then. it is not so clearwhether the laboratory data of open-channel turbulence can be applied to river turbulence at very high Reynolds numbers.
In this study, the to measurements of the Biwa-Sosui River at Re=8x10⁵ have been conducted using three-component electromagnetic flow meters. As the result, it was first found that multi-cellular secondary currents really existed in the river at high Reynolds numbers. The features of secondary currents in rivers were in a good agreement with those in laboratory flumes.