The Temporal and Spatial Evolution of Momentum, Kinetic Energy and Force in Tsunami Waves during Breaking and Inundation

TL;DR

This study uses 3D simulations to analyze how momentum, energy, and force evolve in tsunami waves during breaking, revealing that maximum destructive force occurs early near the shoreline, informing structural design considerations.

Contribution

It provides new insights into the spatial-temporal evolution of flow force, momentum, and energy during tsunami breaking, emphasizing the importance of early shoreline dynamics.

Findings

Flow force peaks before momentum and energy during breaking.

Maximum destructive capacity occurs near the initial shoreline.

Early shoreline dynamics are critical for structural safety design.

Abstract

A plethora of studies in the past decade describe tsunami hazards and study their evolution from the source to the target coastline, but mainly focus on coastal inundation and maximum runup. Nonetheless, anecdotal reports from eyewitnesses, photographs and videos suggest counterintuitive flow dynamics, for example rapid initial acceleration when the wave first strikes the initial shoreline. Further, the details of the flow field at or within tens of meters of the shoreline are exquisitely important in determining damage to structures and evacuation times. Based on a set of three-dimensional numerical simulations using solitary waves as a model, we show the spatial-temporal distribution of the flow momentum, kinetic energy and force during the breaking process. We infer that the flow reaches its highest destructive capacity not when flow momentum or kinetic energy reach their maxima, but when flow force reaches its. This occurs in the initial shoreline environment, which needs to be considered in nearshore structures design.