圆柱形声学外隐身罩的时域研究
Time-domain investigation of a cylindrical acoustic external cloak
摘要：
基于非单调变换的空间折叠技术导致一类新的圆柱形各向同性声学斗篷具有恒定的负密度和空间变化的负体积模量。我们考虑一个由具有正定密度矩阵和正压缩性的核和同时具有负密度和负压缩性的壳组成的外部斗篷。这样的核-壳谐振系统在壳外部产生虚拟折叠区域。为了在时域中处理这样的负物理参数，使用两步策略：（i）在频域中假设谐振（Drude型）有效参数;（ii）通过应用辅助场的形式主义返回到时域。我们的数值计算表明，在设计的中心频率，散射的圆柱形压力波入射在一组有限的小刚性障碍物后，经过一段时间后，大大减少，当他们被放置在附近的外部斗篷。然而，在短时间内，外部斗篷表现得更像一个超散射体：斗篷本身的散射比散射体集更多。
英文摘要：
Space folding techniques based on non-monotonic transforms lead to a new class of cylindrical isotropic acoustic cloaks with a constant negative density and a spatially varying negative bulk modulus. We consider an external cloak consisting of a core with a positive definite density matrix and a positive compressibility, and a shell with simultaneously negative density and compressibility. Such a core-shell resonant system creates a virtual folded region outside the shell. To handle such negative physical parameters in the time-domain, a two-step strategy is used: (i) assuming resonant (Drude-type) effective parameters in the frequency-domain; (ii) returning to the time-domain by applying the formalism of the auxiliary fields. We numerically show that, at the designed central frequency, scattering of a cylindrical pressure wave incident upon a finite set of small rigid obstacles is drastically reduced after a lapse of time, when they are placed in the close neighborhood of the external cloak. However, at short times, the external cloak behaves rather like a superscatterer: the cloak itself scatters more than the set of scatterers.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
