Shielding of rotor noise by plates and wings

TL;DR

This paper develops an approximate analytical method to evaluate how plates and wings can shield rotor noise in aircraft, focusing on noise sources near edges and validating the approach against numerical simulations.

Contribution

It introduces a new approximate analysis for acoustic shielding by plates, applicable to small sources near edges, enhancing understanding of noise reduction strategies in aircraft design.

Findings

Approximate analysis matches numerical results for small sources.

Shielding effectiveness depends on source position and plate geometry.

Method provides a practical tool for designing quieter aircraft.

Abstract

A method of noise reduction proposed for the next generation of aircraft is to shield noise from the propulsion system, by positioning the noise source over a wing or another surface. In this paper, an approximate analysis is developed for the acoustic field far from a circular source placed near the edge of a semi-infinite plate, a model problem for shielding of noise by a wing and for scattering by a trailing edge. The approximation is developed for a source of small radius and is found to be accurate when compared to full numerical evaluation of the field.