Acoustic nonreciprocity in Coriolis mean flow systems

Abstract

ABSTRACT:One way to break acoustic reciprocity is to have a moving wave propagation medium. If the acoustic wave vector and the moving fluid velocity are collinear we can use the wave vector shift caused by the fluid flow to break reciprocity. In this paper we investigated an alternative approach in which the fluid velocity enters the differential equation of the system as a cross product term with the wave vector. A circular field where the fluid velocity increases radially has a Coriolis acceleration term. In such a system, the acoustic wave enters from the central wall and exits from the perimeter wall. In this paper, we solved the differential equation numerically and investigated the effect of fluid velocity on the nonreciprocity factor.

Non-reciprocal scattering in shear flow

“…Adding flow to an acoustic system is one of the simplest ways to make it non-reciprocal. Recently, it has been used to obtain sound isolation 16 or asymmetric propagation 39 , in the broad context of research on unidirectional transmission devices for acoustic waves 17,32 . It appears that sound-flow interactions have been studied for a very long time 42 , early works being motivated by the study of the deflection of sound in the wind 12 .…”