Development and design of marine metamaterials for realizing cloaking of a floating body

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14511
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Naval and maritime engineering
• Research Institution: Osaka University
• Principal Investigator: KASHIWAGI MASASHI 大阪大学, 工学研究科, 教授 (00161026)
• Co-Investigator(Renkei-kenkyūsha): MINOURA MUNEHIKO 大阪大学, 大学院工学研究科, 准教授 (30294044)
• Research Collaborator: IIDA TAKAHITO 大阪大学, 大学院工学研究科, 大学院学生 ; MIKI MARIKO 大阪大学, 大学院工学研究科, 大学院学生 ; ASAUMI TAIGA 大阪大学, 大学院工学研究科, 大学院学生
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: クローキング / 波浪制御 / メタマテリアル / 波浪エネルギー / 波漂流力 / 弾性膜 / 水深テンソル / 負の屈折率

Outline of Final Research Achievements

As a method to realize the cloaking of a floating body in water waves, first, by using a number of smaller circular cylinders and elastic membrane placed around the floating body, various research results were obtained for realizing confinement of scattered waves and hence cloaking, wave-energy absorption, and practically zero wave drift force. Then, under the shallow-wave approximation, we could find the water-depth tensor by using a coordinate transformation that gives deformation of the spatial shape but the same governing equation and boundary conditions. Numerical computation confirmed that the water-depth tensor can be achieved using the homogenization method which can realize the cloaking. In addition, a special cross-channel network composed of a group of small rectangular bodies can realize the negative refraction index implying that the incident wave is bent into an opposite direction and also the backward propagating wave.

Free Research Field

海洋流体工学