Reflected wave manipulation by acoustic metasurface in a grazing shear flow

Renhao Qu, Jingwen Guo, Yi Fang, Wei Yi, Siyang Zhong, David Angland, Xin Zhang

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

Abstract

Acoustic metasurfaces (AMs) are artificial structures that can realize exotic properties, such as negative refraction and perfect absorption, etc., in sub-wavelength thickness scales. Most of the previous studies on AMs were conducted in laboratory conditions with a static medium, limiting their applications in practical conditions, e.g., the aircraft engines where an aerodynamic background flow is present. To fill this gap, the effect of a grazing shear flow on the reflection performance of AMs with periodic construction is studied. An AMs design method is proposed to realize effective wavefront manipulation with the consideration of the shear flow. The strategy is to form a linear reflected phase-shifting covering 0 to 2π at the interference plane between the uniform and the shear flow regions. To validate the effectiveness of the proposed design method, two acoustic porous metasurfaces (APMs), APM1 for the uniform flow and APM2 for the shear flow, are designed and their reflection characteristics are numerically investigated. Results show that the presence of the shear layer deteriorates the effectiveness of APM1 under oblique incidences due to the considerable refraction effect. In contrast, APM2 realizes reflection wavefront manipulation, such as anomalous reflection and surface wave conversion, under the same conditions. This study provides a guideline for AMs design in flow conditions, which offers potential for noise control in aeroacoustic problems.

Original languageEnglish
Title of host publication28th AIAA/CEAS Aeroacoustics Conference, 2022
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
ISBN (Print)9781624106644
DOIs
Publication statusPublished - Jun 2022
Externally publishedYes
Event28th AIAA/CEAS Aeroacoustics Conference, 2022 - Southampton, United Kingdom
Duration: 14 Jun 202217 Jun 2022

Publication series

Name28th AIAA/CEAS Aeroacoustics Conference, 2022

Conference

Conference28th AIAA/CEAS Aeroacoustics Conference, 2022
Country/TerritoryUnited Kingdom
CitySouthampton
Period14/06/2217/06/22

ASJC Scopus subject areas

  • Aerospace Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering

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