3D COMPUTATIONS ON DRIFTWOOD JAMMING AROUND BRIDGE PIERS

Abstract

 A 3D-3D coupling model was constructed for simulating the jamming process by the driftwood around bridge piers. The model of water flow was URANS type, and the driftwood was expressed as connected spheres. The collision between driftwood was evaluated by the discrete element method. Computations were carried out under the same conditions as the previous experiment. We employed the modified driftwood Richardson number (DRI) as a dimensionless number governing the three-dimensionality of driftwood jamming. Computational results showed that the capture ratio increases and the sink ration decreases with the increase of DRI. The tendency was in qualitative agreement with previous experimental result. However, the present computation overestimated the three-dimensionality of driftwood jamming.