Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices

Acoustic liners perforated with thousands of millimeter-size circular orifices are widely used on aero-engines as an effective noise damper. To investigate and optimize the aeroacoustic damping behavior of these perforated liners, numerical simulations of in-duct orifices are performed first. For this,...

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Main Author: Ji, Chenzhen
Other Authors: School of Mechanical and Aerospace Engineering
Format: Theses and Dissertations
Language:English
Published: 2016
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Online Access:http://hdl.handle.net/10356/65968
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-659682023-03-11T16:52:01Z Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices Ji, Chenzhen School of Mechanical and Aerospace Engineering Dan Zhao DRNTU::Engineering::Aeronautical engineering Acoustic liners perforated with thousands of millimeter-size circular orifices are widely used on aero-engines as an effective noise damper. To investigate and optimize the aeroacoustic damping behavior of these perforated liners, numerical simulations of in-duct orifices are performed first. For this, both two- and three-dimensional numerical models of acoustically excited flow through perforated orifices with different geometric shapes are conducted in the time domain by using the lattice Boltzmann method. It is shown that vortex rings are formed when incident sound waves interact with and destabilize the shear layers formed at the orifice rims, and the sound energy is converted into kinetic energy being dissipated by the surrounding air. Unlike frequency-domain simulations typically found in the literature, the damping behavior of the orifices is quantified in the present work over a broad frequency range at a time by forcing an oscillating flow with multiple tones. Good agreement is observed between numerical results with the ones obtained from theoretical models. Parametric study is then conducted. It is found that the damping performance depends on the mean flow, the plate thickness, the orifices’geometric shape and dimensions. Doctor of Philosophy (MAE) 2016-02-10T02:49:18Z 2016-02-10T02:49:18Z 2016 Thesis Ji, C. (2016). Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices. Doctoral thesis, Nanyang Technological University, Singapore. http://hdl.handle.net/10356/65968 en 220 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Aeronautical engineering
spellingShingle DRNTU::Engineering::Aeronautical engineering
Ji, Chenzhen
Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
description Acoustic liners perforated with thousands of millimeter-size circular orifices are widely used on aero-engines as an effective noise damper. To investigate and optimize the aeroacoustic damping behavior of these perforated liners, numerical simulations of in-duct orifices are performed first. For this, both two- and three-dimensional numerical models of acoustically excited flow through perforated orifices with different geometric shapes are conducted in the time domain by using the lattice Boltzmann method. It is shown that vortex rings are formed when incident sound waves interact with and destabilize the shear layers formed at the orifice rims, and the sound energy is converted into kinetic energy being dissipated by the surrounding air. Unlike frequency-domain simulations typically found in the literature, the damping behavior of the orifices is quantified in the present work over a broad frequency range at a time by forcing an oscillating flow with multiple tones. Good agreement is observed between numerical results with the ones obtained from theoretical models. Parametric study is then conducted. It is found that the damping performance depends on the mean flow, the plate thickness, the orifices’geometric shape and dimensions.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Ji, Chenzhen
format Theses and Dissertations
author Ji, Chenzhen
author_sort Ji, Chenzhen
title Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
title_short Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
title_full Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
title_fullStr Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
title_full_unstemmed Numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
title_sort numerical and experimental investigation of aeroacoustic damping characteristics of perforated orifices
publishDate 2016
url http://hdl.handle.net/10356/65968
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