HR: 14:00h
AN: H43A-01    [Abstracts]
TI: Numerical and Experimental Investigations of Tsunami-Induced Sediment Transport
AU: * Young, Y
EM: yyoung@princeton.edu
AF: Princeton University, Dept. of Civil & Env. Engineering, EQUAD E-326 Princeton University, Princeton, NJ 08544, United States
AU: Xiao, H
EM: xiao@princeton.edu
AF: Princeton University, Dept. of Civil & Env. Engineering, EQUAD E-326 Princeton University, Princeton, NJ 08544, United States
AB: As demonstrated by the 2004 Indian Ocean Tsunami, high intensity wave runup and drawdown can mobilize substantial amount of sediment deposits. The resulting erosion and scour damage can undermine building foundations, roadways, sea walls, embankments, and may even lead to eventual collapse of the coastal structure. However, most previous models ignore the effect of tsunami-induced sediment transport and scour due to the complex physics and multiple scaling issues. In this work, a numerical model is presented for the simulation of solitary waves over a uniform sloped movable bed. The depth averaged nonlinear shallow water equations (SWEs) are used to model long waves, the wave profile gradient method is used to detect wave breaking, and the effect of energy-dissipation due to wave breaking is captured as a bore collapse. The effect of sediment transport is modeled via a passive scalar and is fully coupled with the SWEs to form a complete system. New forms of the erosion and deposition fluxes are introduced to account for the effect of the flow velocity, particle fall velocity, wave profile, and pore pressure gradient. The model is validated by comparing the numerical solutions to the measured bed changes obtained from the cross-shore sediment transport experiment under breaking solitary waves conducted by (Kobayashi & Lawrence 2004). To further validate the numerical model, two sets of experimental studies are planned for 2007. The first experimental study focuses on the effect of enhanced transport due to pore pressure gradients, and will be conducted at the 30-ft long flume in the hydraulics lab at the University of Hawaii using multiple grain sizes. The second experimental study focuses on tsunami-induced sediment transport, and will be conducted at the 160-ft long tsunami wave basin at Oregon State University using fine Oregon beach sand with D50=0.20mm. The experimental setups are shown, and scaling issues for the two movable bed physical models are discussed. Comparisons of the differences and similarities in transport mechanisms for tsunami cross-shore environment and river-type environment are presented.
DE: 1815 Erosion
DE: 1862 Sediment transport (4558)
DE: 4534 Hydrodynamic modeling
DE: 4546 Nearshore processes
DE: 4564 Tsunamis and storm surges
SC: Hydrology [H]
MN: 2007 Joint Assembly