Broadband acoustic focusing effect based on temperature gradient distribution

Abstract

Acoustic focusing effect with broad bandwidth based on the temperature gradient distribution is studied. The propagation paths of the acoustic waves can be controlled by the temperature gradient distribution generated by two heat sources, which is adopted to realize the acoustic focusing effect. This focusing effect arises from the continuous change of the acoustic refractive index induced by the change of temperature, and has no reflection energy loss. Therefore, the acoustic focusing effect has the advantages of broad bandwidth and high focusing performance. In addition, we have investigated the influences of the factors (incident frequency, temperature of heat source, spatial distribution of interface, position of heat source, attenuation coefficient of the medium, and asymmetric distribution of heat source temperature) on the acoustic focusing effect in detail, and verified the feasibility of the acoustic focusing system by using aerogel based on temperature gradient distribution in single medium.