TY - GEN
T1 - Reflected wave manipulation by acoustic metasurface in a grazing shear flow
AU - Qu, Renhao
AU - Guo, Jingwen
AU - Fang, Yi
AU - Yi, Wei
AU - Zhong, Siyang
AU - Angland, David
AU - Zhang, Xin
N1 - Funding Information:
This work is partially supported by the Hong Kong Research Grants Council No.16202519. Renhao Qu and Wei Yi are supported by the PhD studentships from the Hong Kong University of Science and Technology. Jingwen Guo wishes to thank the support of Hong Kong Innovation and Technology Commission (ITC) Project ITS/354/18FP. This work was performed in the Aerodynamics, Acoustics & Noise Control Technology Centre at HKUST (aantc.ust.hk).
Publisher Copyright:
© 2022, American Institute of Aeronautics and Astronautics Inc, AIAA., All rights reserved.
PY - 2022/6
Y1 - 2022/6
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85135028650&partnerID=8YFLogxK
U2 - 10.2514/6.2022-2905
DO - 10.2514/6.2022-2905
M3 - Conference article published in proceeding or book
AN - SCOPUS:85135028650
SN - 9781624106644
T3 - 28th AIAA/CEAS Aeroacoustics Conference, 2022
BT - 28th AIAA/CEAS Aeroacoustics Conference, 2022
PB - American Institute of Aeronautics and Astronautics Inc. (AIAA)
T2 - 28th AIAA/CEAS Aeroacoustics Conference, 2022
Y2 - 14 June 2022 through 17 June 2022
ER -