Study on scale effect of impulsive breaking wave force for numerical simulation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14256
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: National Institute of Maritime, Port and Aviation Technology
• Principal Investigator: Tsuruta Naoki 国立研究開発法人海上・港湾・航空技術研究所, 港湾空港技術研究所, 研究グループ長 (30747861)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 粒子法 / ISPH / 砕波 / 安定化スキーム / 解像度可変 / 消波ブロック / 消波境界 / 数値波動水槽

Outline of Final Research Achievements

During typhoons, there is a problem of high waves with impact pressure caused by wave breaking. Numerical wave tanks are expected to reproduce this phenomenon accurately, however, practical and accurate simulations have not been achieved due to the large computational domain and the huge amount of time required for coastal engineering problems.
In this study, a particle-based numerical wave tank is improved for this problem. First, a stabilizing scheme is developed to accurately and stably treat the breaking waves. In addition, a multi-resolution technique is developed for more efficient simulations. Furthermore, a simplified boundary condition model is developed from a geometric analysis of voids between stacked dissipative blocks to reproduce complex wave breaking states effectively. Their good performances are shown through some benchmarks. The versatility of the numerical wave tank has been successfully improved.

Free Research Field

数値流体力学

Academic Significance and Societal Importance of the Research Achievements

近年巨大化する台風とそれによる海岸・港湾施設の被害増大から，高波に伴う衝撃砕波力の高精度な予測ツールの開発が求められているが，衝撃砕波発生時の流体挙動・力学的機構については，十分な知見が得られていないのが現状である．この解決手段として，数値波動水槽の活用が期待されるが，海岸土木の広大な計算領域を対象とする条件下で複雑な水面変形を伴う砕波現象を十分安定的に解くための計算スキームの開発は未だ十分とは言えない．本研究では，こうした需要に応えるべく砕波を安定的かつ高速に解析が可能な各種計算スキームを開発して，その適用性を示した．これにより，今後，衝撃砕波に関する検討が大きく進むことが期待される．