Aeroacoustics of Jet-Surface Interaction and Passive Solutions for Mitigating Jet-Installation Noise

Doctoral thesis (2022)

Authors

Leandro Rego Wind Energy - Aerospace Engineering
Research Group
Wind Energy (Aerospace Engineering) (TU Delft)
Copyright: © 2022 Leandro Rego
DOI
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https://doi.org/10.4233/uuid:a50e3a9c-af3a-4e4f-836c-80f70c75847c
Aeroacoustics Jet-Installation Noise Permeable Materials Acoustic Liners
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Published Date

2022

Language

English

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Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Wind Energy

Abstract

Aircraft noise levels have been significantly reducedwith the introduction of high-bypass ratio turbofan engines, particularly jet noise due to turbulence mixing. This, however, has led to engines with larger diameters and a closer coupling between them and the airframe. As a result, interactions between the exhaust jet flow and the wing give rise to an acoustic source known as jet-installation noise. In more detail, this source is generated by the impingement of unsteady pressure waves from the jet mixing-layer on the airframe surfaces and their scattering as noise at the wing trailing edge. Jet-installation noise becomes relevant particularly during take-off and approach conditions since the deployed flaps are located closer to the turbulent jet flow. Therefore, this thesis aims to elucidate the physical mechanisms behind jet-installation noise, followed by the development of passive mitigation solutions based on porous material technology and acoustic liners. A study on their effects and working mechanisms is performed, as well as on their feasibility from the aerodynamic perspective.