ABSTRACT

The MPS method is used to analyze behaviors of various fluids. Using elliptical particles, the number of particles can be reduced, thereby reducing the calculation time. However, the elliptical particle model of MPS method has not been verified for the shallow-water long wave phenomenon of tsunamis. In this study, the elliptical particle model was verified in a two-dimensional tsunami simulation. As a result, it was found that elliptical particles can shorten the computation time while still maintaining calculation accuracy and exhibiting comparatively better wave height attenuation reduction than the standard MPS method.

INTRODUCTION

The Numerical calculation of the tsunami phenomenon is crucial and attempts have been made to address this challenge using various methods. The importance of numerical calculation of tsunami is increasing, particularly in light of the signify damage in Japan because of the tsunami caused by the Great East Japan Earthquake of 2011.

The MPS and SPH methods are used to conduct the calculations in many tsunami simulations. A computational method, coupled with the difference method and the SPH method and the shallow-water long wave theory to model a tsunami, was developed (Asai, Miyagawa, Idris, Muhari, and Imamura, 2016). The shock wave pressure and wave height of a tsunami was calculated by the MPS method, and the pressure gradient model was found to be highly accurate. (Iribe, Itori, Nakaza, and Mostafizur, 2011) The advantage of the previous MPS research can express the fluid movement even if the fluid movement changes much, and the disadvantage is that it takes much time to calculate because the same size particles are used in all the calculation area normally.

It is important to note that tsunamis have long wave periods and relatively low attenuation. Moreover, it is necessary to shorten the simulation time. However, while the use of elliptical particles has been verified in a simulation of a dam break (Shibata, Koshizuka, and Masaie, 2016), it has yet to be validated in tsunami simulations. In this study, elliptical particles that are elongated in the horizontal direction were used in a MPS simulation of a shallow water long wave to decrease the number of particles required and reduce the calculation time while maintaining accuracy.

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