EXPERIMENTAL STUDY ON PRODUCTION AND TRACTIVE MECHANISM OF SUBMERGED WOOD IN RIVERS

Abstract

 There are few observational data on the production mechanism of submerged wood and its transport process in rivers, and many unclear points still remain. In this study, we focused on the long-term capturre by the backflow circulation behind a weir as one of the causes, and verified it by model experiments. It was quantitatively shown that the scale of the backflow circulation changes depending on the water level difference between the downstream and upstream of the weir, which affects the capture rate. Further, the critical tractive force is considered for the submerged wood partially buried to the flume bed. For the case of being buried horizontally, empirical formulae for the normalized critical tractive force were proposed. We also dealt with cases of being buried diagonally to the bed, and considered the effect of pitch and yaw angles on the critical tractive force.