Author(s): Takaaki Abe; Yasuhiro Yoshikawa; Hiroya Ogushi
Linked Author(s): yasuhiro yoshikawa
Keywords: Tsunami intrusion into rivers; Hydraulic experiments; Numerical model; Particle simulation model; FDM-MPS coupling
Abstract: In the event of tsunami intrusion in cold-region estuaries and rivers, the ice cover can be broken into pieces and transported by the tsunami waves. The 2011 Tohoku-Pacific Coast Earthquake tsunami intruded ice-covered rivers around the coast line of Hokkaido, Japan. A number of ice floes were found to be deposited around estuarine regions. This paper presents an experimental and numerical investigation on ice run-up and flowing down process caused by tsunami. A series of hydraulic experiments are performed for clarifying the basic behaviors of ice floes. On the basis of these results, a practical model is proposed for predicting ice floe movement with interactions between tsunami, river ice and river channels. A Lagrangian approach, e. g. MPS (Moving Particle Simulation) method is introduced for this objective. The proposed method employs two layers of calculation domain concurrently; the lower layer is finite difference method (FDM) for flow calculation and the upper one is for ice particle movement. The experimental results show that ice floe can cause the blockage of narrow sections and consequent rise in water level in the channel. The calculation results also show the ice blockage induced by tsunami flow. Using this model an important consideration can be obtained in designing cold-region estuarine river channels.
Year: 2024