Experimental analysis of Tsunami–Current interaction in river channel

Abstract

The 2011 Tohoku Tsunami caused severe human and property damage along the east coast of Japan. In particular, the tsunami introduced through the river mouth damaged inland areas as it traveled up the river. In this study, a laboratory experiment was performed by applying funnel-shaped river mouth characteristics to investigate the hydraulic characteristics of a tsunami traveling up a river. In the river channel, the tsunami and wave heights were increased by the non-linear interaction between the tsunami and river current, which intensified as the river flow velocity increased. The river current in the opposite direction delayed tsunami propagation, thereby reducing the average celerity. The dispersion relation of the tsunami increased the time difference between the large first peak and small second peak. Additionally, the river current increased the effective volume of the tsunami wave peak. These hydraulic phenomena occurred because the short-term flow characteristics of the tsunami are stronger than those of oscillating waves in the non-linear interaction between the tsunami and river current. © 2023 Elsevier Ltd