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Showing 1 to 9 of 9 for “"acoustic liner"”.
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Broadband Acoustic Liner Optimization Study Using Novel Poro-elastic Materials
… aircraft engine noise, there is need for acoustic liner configurations that target broadband performance. This thesis experimentally and analytically investigates passive noise control methods to improve broadband frequency attenuation through various acoustic liner designs. The inclusion …
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Improvement In Acoustic Liner Attenuation In Turbofan Engines By Means Of Plasma Synthetic Jet Actuator
… to reduce noise emissions. Turbofan engine acoustic liners are efficient attenuators of engine noise. Plasma actuators have been used as flow control devices in other settings and will now be studied as an enhancement for acoustic liners. A plasma actuator can excite oscillatory flow or a …
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Investigating the Feasibility and Stability for Modeling Acoustic Wave Scattering Using a Time-Domain Boundary Integral Equation with Impedance Boundary Condition
… objective in the field of computational aeroacoustics. When designing next generation quiet and environmentally friendly aircraft, it is important to be able to accurately and efficiently predict the acoustic scattering by an aircraft body from a given noise source. Acoustic liners are an …
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Numerical investigation of slat noise attenuation using acoustic liners
… of attenuating slat noise using absorptive acoustic liners in the slat/main element gap is explored using a time domain computational aeroacoustic (CAA) technique. The aims of the development and application of the computational method are to reveal the mechanism of the slat noise generation …
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The Impact of Surface Roughness on Transonic Inlet Lip-Flows at Incidence
… to surface roughness features, such as the acoustic liner. This is made up of small, tightly packed holes over the inner surface. The acoustic liner is not the only source of roughness during take-off. Other examples include ice which can form around the inlet lip, or insects which impact …
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Aeroacoustic computation of sound radiation from ducts
… is being undertaken to understand the aeroacoustic noise source mechanisms and to accurately predict engine noise levels. High-performance computers and advanced numerical techniques are now taking an active role in this research area. In this work, a numerical solver is developed to …
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Biology-Inspired Approach for Communal Behavior in Massively Deployed Sensor Networks
… and actions, optimal impedance values for an acoustic liner are determined <em>in situ</em> providing the basis for an adaptive noise abatement system that provides superior noise reduction compared with current technology and previous research efforts.</p>
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Direct numerical investigation and reduced-order modeling of 3-D honeycomb acoustic liners
Single degree-of-freedom conventional acoustic liners are widely installed in jet engines to reduce internal engine noise. They work by converting acoustic energy into vorticity-bound fluctuations. Despite being widely used, effective design-stage models of acoustic liners placed in high sound …
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Modeling of Herschel/Quincke-Liner Systems for the Control of Aft Fan Radiation in Turbofan Engines
… technology is that of absorbent materials or liners. In recent investigations Alonso et al. have combined Herschel/Quincke (HQ) tubes with liners. This combination has the potential of effectively controlling pure tones and broadband noise in inlet sections of modern turbofan engines. Since a …