Boisvert Jeffrey E, Scandrett Clyde L, Howarth Thomas R
NAVSEA Division Newport, Newport, Rhode Island 02841-5047, USA.
Department of Applied Mathematics, Naval Postgraduate School, Monterey, California 93943, USA.
J Acoust Soc Am. 2016 Jun;139(6):3404. doi: 10.1121/1.4949541.
Transformational acoustics offers the theoretical possibility of cloaking obstacles within fluids, provided metamaterials having continuously varying bulk moduli and densities can be found or constructed. Realistically, materials with the proper, continuously varying anisotropies do not presently exist. However, discretely layered cloaks having constant material parameters within each layer may be a viable alternative in practice. The present work considers a range of cloaks, from those comprised of fluid layers that are isotropic in bulk moduli with anisotropic density (inertial cloaks) to those having anisotropic bulk moduli and isotropic density (pentamode cloaks). In this paper an analytical solution is obtained for the case of plane wave scattering from a submerged rigid cylinder covered with a multilayered cylindrical cloak composed of discrete anisotropic fluid layers. An investigation of the parameter space defining such cloaks is undertaken with the goal of minimizing the far-field scattered pressure, using layer constituent anisotropic properties (density and bulk modulus) constrained to lie within reasonable ranges relative to those of water.
变换声学提供了在流体中使障碍物隐形的理论可能性，前提是能够找到或构建具有连续变化的体积模量和密度的超材料。实际上，目前并不存在具有适当的、连续变化的各向异性的材料。然而，在实践中，每层具有恒定材料参数的离散分层隐身衣可能是一种可行的替代方案。目前的工作考虑了一系列隐身衣，从那些由体积模量各向同性而密度各向异性的流体层组成的隐身衣（惯性隐身衣）到那些具有各向异性体积模量和各向同性密度的隐身衣（五模隐身衣）。本文针对平面波从覆盖有由离散各向异性流体层组成的多层圆柱形隐身衣的水下刚性圆柱体散射的情况，获得了一个解析解。利用被限制在相对于水的合理范围内的层组成各向异性特性（密度和体积模量），对定义此类隐身衣的参数空间进行了研究，目的是使远场散射压力最小化。
