1. Introduction
The benefits derived from the development of acoustic transistors
have been stressed in the literature in the last few years [1].
Lately, two acoustic diodes have been proposed. The first device
was presented by Liang et al., and relies on nonlinear effects of
bubbly liquids [2,3]. It consists of two segments: a sonic crystal
to filter frequencies and a nonlinear bubbly medium capable to
modify the frequency content of the incident wave. The second device
was proposed by Li et al., and relies on linear effects without
considering any bubbly liquids [4]. It consists of an acoustic metamaterial
as well, coupled to a diffraction structure capable to modify
the spatial frequency of the incident wave, and it can be
switched on and off by rotating one of its parts. These papers
opened a new era in the research on acoustic devices able to behave
like transistor, and researchers have reported the possible
benefits of such new devices, which, like their equivalent systems
in electricity and electronics, may be used as switches or amplifiers
of acoustic waves and eventually integrated into acoustic circuits
[1,5,6]. An acoustic switch, like its equivalent electric device,
should ideally switch a main acoustic wave via the use of another
acoustic wave: the secondary wave manipulates the main wave
and allows the main wave to propagate or not. The aim of this paper
is to study the existence of an acoustic switch based on the
propagation of ultrasounds in bubbly liquids by means of numerical
simulations. It must be noted that the effects of bubbly liquids
on an acoustic field are known [7–14], especially about attenuation
and dispersion for linear acoustic waves. However we use these
properties here to propose a new application of bubbly liquids
through the concept of a new device: an acoustic switch.