EFEECTS OF OBLIQUE WEIR WITH AN OPENING ON RIVER BED TOPOGRAPHY

Abstract

 In this study, the depth of the opening of the oblique weir was systematically changed, and the sand removal function of the sediment deposited upstream of the weir and the riverbed fluctuation downstream of the weir were investigated. The oblique weirs with openings increased the fluidity of sediment deposited upstream of the weir and lowered the riverbed. The scouring section upstream of the weir was divided into a gradually varied flow section and a local flow section based on the bed topography. The experimental results showed that in the gradually varied flow change section, the amount of water level and riverbed degradation increased linearly as the depth of the opening increased, and the river bed degradation of the oblique weir was higher than that of the orthogonal weir. In the local flow section, the scouring holes downstream of the oblique weir were found to be similar in shape by making them dimensionless on a typical length scale, and the effect of opening depth on the representative length scale was clarified.