Analysis of driftwood behavior debouched into a bay by using Eulerian and Lagrangian coupling model

摘要

A large amount of driftwood produced by many slope failures on mountainsides and riverbank erosion was debouched into Beppu Bay because of major flooding of the Ohno River due to heavy rainfall on July 2, 1990 in Oita Prefecture Japan. Direct and indirect damage, i.e. navigation risk to shipping, decreased functioning of harbor facilities, and damage to fish and shellfish farming, were very severe In this paper, a numerical simulation model was presented that used an interacting combination of the Eulerian fluid and Lagrangian driftwood models, in which the effects of wind force on driftwood motion was newly considered. The calculated flow direction of the driftwood was similar to the actual direction and the calculated flow behavior of driftwood in the whirl in the bay was comparatively well reproduced.