On the splash-up of tsunami bore impact

Impulsive forces on a box-shaped structure due to bore impact are investigated experimentally. Experiments are conducted in the laboratory by generating a Gaussian-shaped wave onto a step before impacting structures of three different cross-shore to long-shore length ratios. The relationship between measurements of the splash-up flow on the structure wall and the force measurements is investigated. The pressures are predicted based on the Euler model. Maximum impact forces are found to occur during the run-down phase after the maximum splash-up value is reached. The uniform vertical velocity profile assumption used in the Euler model yields a better estimate for the impact force than the linear and hydrostatic assumptions. In order to verify the pressure distribution during the splash-up flow, we utilize the pressure data collected from a separate experiment in a large-scale laboratory flume. The combined evidence suggests that the flow near the splash-up tip behaves like a solid body projectile.