平面2層位モデルによる複断面流れの渦運動解析

Abstract

In compound open channel flow, it is important to clarify the characteristics of the large scale horizontal vortices which occur at the interface between the main channel and the flood plain due to the shear instability. The momentum transport in the transverse direction induced by the vortices affects the resistance to flow in rivers and river bed configurations during flood. The numerical method based on the plane two-layered flow model is proposed to reproduce efficiently the vortex formation process in a compound open channel with a rectangular main channel. The horizontal and vertical structure of the flow is examined in detail through the comparison of numerical results to the laboratory tests by Ikeda et al. and Fukuoka et al. The increase of the flow resistance induced by horizontal vortices is also estimated numerically by means of the presented model.