Abstract
Localized torrential rains yield large amounts of driftwood in rivers aggravate the flood events. For example, large driftwood blocks the river, which lead to a decreased discharge capacity and increased water levels. However, there is almost no detailed information about the pitching and yawing moment stability of driftwood. In the present study, three kinds of flume experiments (1. Drag force and Lift force measurement, 2. Pitching moment and Yawing measurement, 3. Driftwood accumulation experiment) were performed. We also examined the effect of the gravity center position on the directional stability of driftwood. Particularly, small increase in angle of attack caused a significant increase of the projected area of driftwood. The results revealed that the blocking probability of driftwood at bridge decks and backwater rise due to driftwood accumulation depend on the projected area of driftwood.
