Numerical study on the causes of breaking waves and the relationship between breaking waves and impact pressure

Research Project

Project/Area Number	16K17553
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Computational science
Research Institution	University of the Ryukyus
Principal Investigator	IRIBE Tsunakiyo 琉球大学, 工学部, 助教 (20608731)
Project Period (FY)	2016-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000) Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2016: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Keywords	砕波 / 力学的なエネルギー / 水表面 / 運動エネルギー / 計算力学 / 衝撃波圧 / 力学的エネルギー
Outline of Final Research Achievements	The purposes of this study are to clarify the causes of breaking waves and to disclose the relationship between breaking waves and impact pressure by the numerical simulation. Numerical simulations of wave run-up on the periodic wave and the solitary wave have been conducted to analyze the mechanical energy on water surface. The results show that the kinetic energy of water surface particles increases divergently which can lead to the wave breaking. However, impact pressure is difficult to elucidate only with the wave pressure just after the wave breaking.
Academic Significance and Societal Importance of the Research Achievements	本研究の成果である砕波条件の学術的意義は，砕波が波峰以外の位置で起こることを示唆したことである。また，社会的意義としては社会インフラの維持管理にも役立つと考えられる。例えば，砕波は空気中への塩分供給の原因であり，その塩分が構造物に付着すると構造物は劣化し始める。従って，数値シミュレーションなどで砕波点の正確な位置を算出し，現地観測から得られる風況と組み合わせることで，海岸からの飛来塩分量を高精度に予測することができる。