Figure 26.

(a) Calculated pressure map for a planar longitudinal wave incident on a rigid cylindrical scatterer surrounded by a multilayered acoustic shell made up of 200 layers (see inset). Reproduced with permission.³⁷⁸ Copyright 2008, IOP Publishing Ltd. (b) Oblique-view photograph of a cloaking device made of PVC before filling with PDMS and experimentally measured displacement fields passing by a solid disk with and without the cloak device at 200 Hz. Reproduced with permission.³⁸¹ Copyright 2012, American Physical Society. (c) Photographs of a ground cloaking cover consisting of perforated plates are shown with the unit cell and simulated acoustic signatures of a triangular object with and without the cloaking cover. Reproduced with permission.³⁸² Copyright 2011, American Physical Society.