Simulation on tsunami-like solitary wave run-up around a conical island using a modified mass source method

Zhe Ma,Ting Zhou,Jiawen Sun,Gangjun Zhai

doi:10.1080/19942060.2019.1642960

Zhe Ma, Ting Zhou + Show 2 more

Open Access

https://doi.org/10.1080/19942060.2019.1642960

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Abstract

Predicting the maximum run-up height and inundated area caused by tsunami events has been a hotly debated topic recently. Nevertheless, the wave height-to-depth ratios (nonlinearity) adapted previously tended to be conservative, considering the fact that a tsunami wave is an extreme wave condition with large wave height. In the present study, a mass source wave-generating approach for highly nonlinear waves is presented using our in-house solver, DUT-FOAM, which is a hydrodynamic solver developed using the open source code library OpenFOAM. By fully considering the mass output from the source region, a more reasonable mass source function has been obtained to compensate for the inadequacy of original method in simulating highly nonlinear waves. A newly designed numerical wave tank is performed for different nonlinearities. Numerical simulations of tsunami wave propagating to a conical island are carried. Fairly good agreements are obtained from the qualitative and quantitative comparisons between numerical results (Liu, Cho, Briggs, Kanoglu, & Synolakis, 1995) and laboratory data (Briggs, Synolakis, Harkins, & Green, 1995) regarding run-up maps around the island. The comparison reveals that present model offers a fast and accurate way to simulate highly nonlinear waves and is potentially useful and efficient for forecasting the run-up heights.

Highlights

As a sudden and devastating natural marine disaster, tsunamis are generally caused by natural geological disasters, such as seabed earthquakes, volcanic eruptions, and submarine landslides
We present a numerical simulation of solitary wave run-up around a conical island and propose a modified mass source method within our inhouse solver DUT-FOAM to improve the accuracy of the simulation of highly nonlinear waves
Since waves were nonbreaking until the final stages of transformation near the shoreline where gentle spilling occurred in the experiment (Briggs et al, 1995), in the numerical model the laminar flow is applied with effective wave-absorption regions at two ends of the wave tank

Summary

Introduction

As a sudden and devastating natural marine disaster, tsunamis are generally caused by natural geological disasters, such as seabed earthquakes, volcanic eruptions, and submarine landslides. A destructive tsunami hit Indonesia on December 22, 2018, killing at least 222 people and injuring 843 on the Sunda Strait When facing a tsunami attack, the direct damages for an island are wave run-up and inundation. A tsunami in Indonesia in 1992 caused unexpectedly huge run-up heights on the lee shore of Babi Island, killing more than 700 people according to Imamura, Gica, Takahashi, and Shuto (1995) and Paris, Lavigne, Wassmer, and Sartohadi (2007). The 1993 Southwest Hokkaido earthquake tsunami caused great damage and losses around the southern part of Okushiri Island (Sato, 1996). Studying tsunami waves’ run-up and inundation rules to assess this kind of disaster is of great significance for the development and maintenance of existing islands as well as for the design and construction of artificial ones

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