Author(s): Gregory S De Costa; Taisuke Ishigaki; Y Morimoto; T Ozaki; K Toda
Linked Author(s): Taisuke Ishigaki
Keywords: Drifting conditions; Flooding; Buoyancy
Abstract: Severe rainstorms have induced devastating damages to New Zealand and Japanese cities in the last decades. In this paper, critical flow velocity and water depth for vehicle floating and transfer has been investigated by model tests, and drifting velocity of vehicle was also measured. Two kinds of experiment were conducted by using a tilting channel of15m long, 0.5m wide and 0.25m deep. One is the measurement of critical flow velocity and water depth for vehicle transfer. And the other is the measurement of drifting velocity of vehicle on the super critical conditions. The channel slopes were set at the six conditions of level, 1/800,1/400,1/200,1/100 and 1/50. Flows in the cases of level, 1/800 and1/400 are subcritical flow, and those on the cases over 1/200 are super critical flow. It was found that, in the subcritical flow, the critical conditions depend on flow velocity, not on water depth. The critical velocity is around 1.5 m/s. The drifting velocity in the supercritical condition is about 60 to 80 percent of flow velocity which is as same as the velocity of drifting particle in river flood.
Year: 2014