Phys.org July 28, 2022
Aided by a reflecting surface, the acoustic carpet cloak has become one of the most practically feasible invisibility devices. However, due to the difficulty in the realization of ideal material parameters, the underwater carpet cloaks could only work for a small incident angle. Researchers in China designed an underwater carpet cloak using a three-component metafluid composed of syntactic foam, steel, and water. The syntactic foam, which is synthesized from epoxy resin and hollow glass microspheres, exhibits lower mass density and higher sound velocity relative to water. By periodically embedding the syntactic foam and steel rods in water, they constructed a carpet cloak and experimentally demonstrated it in an anechoic water tank. The results indicated that the cloak works well under both normal and oblique incidences for broadband frequencies. According to the researchers their work paves the way for future applications and the syntactic foam in the design provides an extra degree of freedom for the acoustic parameter regulation…read more. TECHNICAL ARTICLEÂ
Characterization of the syntactic foam. Credit: Phys. Rev. Applied 18, 014050, 20 July 2022Â