Extraordinary acoustic shielding by a monolayer of periodical polymethyl methacrylate cylinders immersed in water

We study, both experimentally and numerically, the acoustic transmission through a monolayer of periodical polymethyl methacrylate cylinders immersed in water. Beyond our expectation, nearly-total reflection is observed for the system, consisting of two ingredients with low impedance contrast. Our investigation manifests that this extraordinary acoustic shielding mostly stems from the resonant excitation of the localized Stoneley surface waves in individual cylinders. Such local modes are rooted in the complicated coupling between the longitudinal and transverse waves and are unique in acoustic systems. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601746]