An Acoustic Liner with a Multilayered Active Facesheet

Dodge, Chelsea; Howerton, Brian M.; Jones, Michael G.

doi:10.2514/6.2022-2902

Cited by 5 publications

(3 citation statements)

References 3 publications

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“…A large shift in the resonant frequency of 500-600 Hz was measured when the smart polymer was activated. A shape memory alloy wire was integrated into a multilayered facesheet in Kreitzman et al 7 and Dodge et al 8 By misaligning one of the facesheet layers, the effective hole diameter of the facesheet could be changed, resulting in a resonant frequency shift of 350 Hz, or 30%. Rather than modifying the physical dimensions of the liner, other researchers have incorporated compliant and electrical components into active liners.…”

Section: Introductionmentioning

confidence: 99%

Modeling, design, and optimization of a dielectric elastomer acoustic liner

Solano,

Cattafesta

2023

International Journal of Aeroacoustics

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The modeling, design, and optimization of an embedded dielectric elastomer (DE) membrane acoustic liner is considered. The acoustic impedance of the liner is modified when the DE is subjected to voltage, resulting in a reduction of the in-plane stress. A lumped element model of an embedded dielectric elastomer acoustic liner is derived and validated in a normal incidence impedance tube and is subsequently used to optimize its performance. The optimization cost functions include (1) maximization of the average absorption coefficient over a targeted frequency range, 400 – 1600 Hz and (2) maximization of the change in the liner fundamental resonance frequency when the membrane is activated. Good agreement between measured and predicted absorption is observed. Tuning of the resonant frequency requires a numerical solution for resonance using the imaginary part of the impedance, since a simple analytical expression for resonance cannot be derived due to the complex coupling between the acoustics of the liner and the electro-mechanics of the DE membrane. Nonetheless, resonant frequency shifts predicted with the lumped element model compare favorably to those measured with the activated liner sample, with a shift of 213 Hz.

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Section: Introductionmentioning

confidence: 99%

Modeling, design, and optimization of a dielectric elastomer acoustic liner

Solano,

Cattafesta

2023

International Journal of Aeroacoustics

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“…The research on noise reduction devices is nowadays very active in all the aircraft areas, involving relatively mature technologies for quieter high lift devices [3], chevrons for jet exhaust [4,5], the evolution of acoustic liners [6][7][8][9][10][11] for turbofans ducts, and also more innovative treatments with lower Technology Readiness Level [12]. Jet noise has always been a dominant noise source for turbojets and turbofans especially during take-off operations.…”

Section: Introductionmentioning

confidence: 99%

Subsonic installed Jet noise scattering prediction using BEM and near-field-data-optimized Wave-Packet model

Palma

Meloni

Camussi

et al. 2023

AIAA AVIATION 2023 Forum

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The propulsion-airframe acoustic interaction is an aspect of growing interest in aircraft noise assessment. The development of low-order models for the jet noise source is vital to address the scattering from the surfaces with computational costs compatible with the conceptual or preliminary design phase when complete computational fluid dynamics simulations are not yet affordable for the effort and time required. In this study, we use a jet-noise wave-packet model capable of modelling both the hydrodynamic and acoustic part of the pressure fluctuations. The model parameters are optimized using near-and far-field information from a large eddy simulation of a free subsonic jet at multiple radial distances. The use of near-field data is based on the observation that the scattering surfaces are typically separated from the jet axis in the radial direction only by a few nozzle diameters. The noise source is then implemented in an in-house open-source Boundary Element Method code (AcouSTO), solving the Kirchhoff-Helmholtz equation to evaluate the scattering and propagation of the pressure perturbation in the far field. The BEM simulations show an increased directivity in the upstream direction for the installed jet, in agreement with the observation presented in the literature.

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“…The design of a modern commercial aircraft must consider the acoustic emissions from the early conceptual phase, hence reliable and fast prediction methods are of fundamental importance. Tremendous efforts have been and are being deployed in the development of more effective acoustic treatments and devices for quieter aviation, such as quieter high lift devices [1], chevrons for jet exhaust [2,3], acoustic liners, and/or innovative treatments [4][5][6][7][8] for turbofans ducts. Innovative configurations are being studied to avoid technological saturation in the race for aviation noise abatement.…”

Section: Introductionmentioning

confidence: 99%

Data-Driven Multiobjective Optimization of Wave-Packets for Near-Field Subsonic Jet Noise

et al. 2023

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Aeroacoustics of innovative aircraft cannot disregard the development of low-order models for the jet noise source, which are essential to assess the propulsion–airframe interactions from the conceptual design stage. The main scope of this work is to provide a noise source model that can be coupled with relatively low computational cost methods for aeroacoustic scattering. To this end, this paper presents for the first time a multiobjective optimization of the zeroth-mode wave-packet in the jet near field. The importance of calibrating the model with near-field pressure data stems from the fact that in new aircraft, the engine nacelles are typically positioned at a few diameters from the wing or fuselage. In this work, the near field of a high subsonic jet at a Mach number of 0.9 is represented as a cylindrical surface radiating the pressure disturbances of a wave-packet source, which is optimized using large-eddy simulation data from three lines at different radial distances. The optimized model has been tested at Strouhal numbers between 0.25 and one, and the optimized solutions have been chosen using a Pareto-ranking criterion considering the wave-packet prediction over an extra line. A good agreement is achieved between the reference data and model predictions for multiple near-field radial distances.

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An Acoustic Liner with a Multilayered Active Facesheet

Cited by 5 publications

References 3 publications

Modeling, design, and optimization of a dielectric elastomer acoustic liner

Modeling, design, and optimization of a dielectric elastomer acoustic liner

Subsonic installed Jet noise scattering prediction using BEM and near-field-data-optimized Wave-Packet model

Data-Driven Multiobjective Optimization of Wave-Packets for Near-Field Subsonic Jet Noise

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