TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 64 (No. 10), pp. 965-972, 2012

Three-dimensional numerical analysis to predict behavior of driftage carried by tsunami

Nozomu Yoneyama1, Hiroshi Nagashima2, and Keiichi Toda1

1Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 6110011, Japan
2Newjec Inc., 2-3-20 Honjohigashi, Kita, Osaka 5310074, Japan

(Received December 7, 2010; Revised November 5, 2011; Accepted November 30, 2011; Online published October 24, 2012)

Abstract: This study aims to develop a three-dimensional (3D) numerical analysis code for the prediction of driftage behavior during a tsunami. The main features of this code are as follows: (1) it can simulate the six degree-of-freedom motion of driftage in a 3D flow field; (2) it can consider the interaction between fluid flow and driftage motion; and (3) it can compute the impact of the collision with a wall based on the Lagrangian equation of impulsive motion. In this code, we assume that the fluid pressure and viscosity cause driftage motion and that driftage motion affects fluid flow through deformation of the boundary between the fluid and itself. The code was applied to a hydraulic experiment carried out by subjecting a wooden body to an abrupt flow of water. The obtained numerical solution of driftage motion agreed well with the experimental result. It is concluded that our code can be used to successfully predict the behavior of driftage carried by a tsunami.
Key words: Three-dimensional numerical analysis, tsunami, driftage, six degree-of-freedom motion.

Corresponding author E-mail: yoneyama.nozomu.4w@kyoto-u.ac.jp

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