Tunable acoustic couplers for two fluids with large impedance mismatch

Abstract

The tunneling effects of acoustics have been found when the proposed solid–fluid superlattices (SLs) are used to match two fluids with a large impedance mismatch. One of the examples shows that, by embedding a rubber/water SL between air and crude oil, the transmission of acoustic energy reaches 0.97 at 5° at 8.73 kHz. According to the results of theoretical analyses and full-wave simulations, this energy tunneling is attributed to the acoustically resonant states induced by the SL at the interface. The tunneling frequencies can be tuned in real time by varying the interspacing between the solid layers of the SL, which may have wide potential applications in matching two fluids, such as acoustic coupling between air and crude oil during petroleum exploration.