Acoustic Cloaking via Homogenization

AcousticAcoustics cloakingCloaking is theAcoustic cloaking mechanism representingHomogenization the ideal acousticAcoustics stealth. We introduce and discuss the acousticAcoustics cloakCloak, a material shellShells that renders an object acousticallyAcoustically ‘invisible’ thanks to its presence surrounding the object. It has been shown that cloaking shellsCloaking shell require very complex parameters to be realized. This complexity comes from the fact that their acousticAcoustics parameters must be anisotropicAnisotropic, inhomogeneous and divergent near the cloaked object. This chapter explains how to engineer artificial structures, which have been called acoustic metamaterialsAcoustic metamaterial or metafluidsAcoustic metafluids, that respond dynamically as anisotropicAnisotropic and inhomogeneous materials. The metafluidsMetafluid are made from arraysArray of isotropic and homogeneous elasticElastic cylinders or by metallic platesPlate cylindrically corrugated. We also propose solutions to remove the divergences appearing in the design of cloaking shellsCloaking shell. It is therefore predicted that, although difficult to realize, cloaking shellsCloaking shell are not impossible by using metafluidsMetafluid based on the homogenizationHomogenization of periodic structuresPeriodic structures.