Abnormal acoustic transmission in a waveguide with perforated screens

TL;DR

This paper investigates how precise tuning of the distance between perforated screens in an acoustic waveguide can enable near-complete transmission of sound, despite typical energy blockage caused by the screens' geometry.

Contribution

It provides an explicit, non-intuitive criterion for achieving near-total acoustic transmission through a waveguide with perforated screens, supported by numerical validation.

Findings

Near-complete transmission occurs at specific screen spacing.

Explicit criterion for resonance-based transmission.

Numerical experiments confirm theoretical predictions.

Abstract

We consider the propagation of the piston mode in an acoustic waveguide obstructed by two screens with small holes. In general, due to the features of the geometry, almost no energy of the incident wave is transmitted through the structure. The goal of this article is to show that tuning carefully the distance between the two screens, which form a resonator, one can get almost complete transmission. We obtain an explicit criterion, not so obvious to intuit, for this phenomenon to happen. Numerical experiments illustrate the analysis.