Scattering of Sound Waves by a Canonical Acoustic Hole

TL;DR

This paper investigates how sound waves scatter off a canonical acoustic hole, revealing similarities with black hole scattering, including interference patterns and a backward scattering peak, with potential for experimental observation.

Contribution

It introduces a detailed analysis of acoustic wave scattering by a canonical acoustic hole, highlighting key features like the glory effect and quantitative comparisons with black hole scattering.

Findings

Identified regular oscillations in scattered intensity due to wavefront interference.

Demonstrated a backward scattering peak (glory) with reduced intensity compared to black holes.

Quantified the glory's relative strength, approximately 170 times less intense than in Schwarzschild black holes.

Abstract

This is a study of a monochromatic planar perturbation impinging upon a canonical acoustic hole. We show that acoustic hole scattering shares key features with black hole scattering. The interference of wavefronts passing in opposite senses around the hole creates regular oscillations in the scattered intensity. We examine this effect by applying a partial wave method to compute the differential scattering cross section for a range of incident wavelengths. We demonstrate the existence of a scattering peak in the backward direction, known as the glory. We show that the glory created by the canonical acoustic hole is approximately 170 times less intense than the glory created by the Schwarzschild black hole, for equivalent horizon-to-wavelength ratios. We hope that direct experimental observations of such effects may be possible in the near future.