FUNDAMENTAL STUDY ON DOWNSTREAM PATHWAY OF SUBMERGED WOOD

Abstract

 When a large flood event occurs, the submerged wood are expected to be transported downstream and damage river structures as gates and weirs. Hence, it is required to predict time-dependent distribution of submerged woods and related numerical simulation. However, the transport characteristics of submerged wood are unknown due to the light specific density and directional shape compared to the bed load material. The existing theory of sediment transport cannot cover them. Therefore, this study conducted hydraulic experiments to obtain a fundamental knowledge. An image analysis with color tracking method was applied to time-series of the yaw angle / horizontal position of the submerged wood model and the traveling distance until contact with side walls. Particularly, we considered influences of wood length and root. The longer wood is transferred more stably. The initial yaw angle and root change the motion patterns and the traveling distance.