Acoustic Analogue of Gravitational Wave

TL;DR

This paper demonstrates that nonlinear perturbations in static fluid systems can be described by a massless scalar field in a time-dependent acoustic metric, which closely resembles the gravitational wave metric in Minkowski spacetime.

Contribution

It introduces an acoustic analogue of gravitational waves by linking fluid perturbations to a scalar field in a dynamic acoustic metric, revealing new parallels with gravitational wave physics.

Findings

Perturbations satisfy a massless scalar field equation in a dynamic acoustic metric.

The acoustic metric derived from fluid perturbations resembles the gravitational wave metric.

Second-order perturbations reveal similarities with gravitational wave behavior.

Abstract

We explore nonlinear perturbations in different static fluid systems. We find that the equations, corresponding to the perturbation of the integrals of motion, i.e; Bernoulli's constant and the mass flow rate, satisfy massless scalar field equation in a time dependent acoustic metric. When one is interested up to the second order behaviour of the perturbations, the emergent time dependent acoustic metric of the system, derived from the massless scalar field equations of the perturbations of the integrals of motion, has some astounding similarities with the metric describing gravitational wave in Minkowski spacetime.