A 3D NUMERICAL STUDY FOR THE CHARASTERISTICS OF TSUNAMIS ASCENDING RIVERS

Abstract

 The tsunamis ascending the rivers, were simulated using a three-dimensional numerical model. The tsunami height, which is the maximum water-surface displacement at each point, increased, as the width of rivers was decreased. When the soliton disintegration occurred in the rivers with a narrow width, the tsunami height increased in the tsunami ascent. Conversely, when no soliton disintegration occurred in the rivers with a wide width, the tsunami height decreased through the tsunami propagation, after the peak of the tsunami height appeared. In the cases determining the tsunamis ascending the rivers with a compound channel, the direction of tsunami propagation became inclined. In the present cases, the tsunami height was lower over the flood plain than the incident tsunami height. If the width of rivers is decreased upstream, the tsunami height increased owing to both the contraction in the river width, and the soliton disintegration.