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Showing 1 to 14 of 14 for “"Airframe Noise"”.
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Clean Wing Airframe Noise Modeling for Multidisciplinary Design and Optimization
A new noise metric has been developed that may be used for optimization problems involving aerodynamic noise from a clean wing. The modeling approach uses a classical trailing edge noise theory as the starting point. The final form of the noise metric includes characteristic velocity and length …
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Multidisciplinary Design Optimization of Low-Noise Transport Aircraft
… of this research is to examine how to design low-noise transport aircraft using Multidisciplinary Design Optimization (MDO). The subject is approached by designing for low-noise both implicitly and explicitly. The explicit design approach involves optimizing an aircraft while explicitly …
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Design trade studies and assessment for advanced quiet aircraft concepts
… for a range of 4,000nm and 250 passengers. A noise assessment was conducted on the engine and airframe noise sources of the resulting design. The noise impacts of five engine (jet, fan forward, fan rearward, core, and turbine) and airframe (airfoil, elevator, slat, drag rudder, and …
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Systems analysis of community noise impacts of advanced flight procedures for conventional and hybrid electric aircraft
… precise navigation technologies have created noise concentration problems for communities beneath flight tracks. There may be opportunities to reduce community noise impacts under these concentrated flight tracks through advanced operational approach and departure procedures and advanced …
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Computational aeroacoustic modelling using hybrid RANS/LES methods with modified acoustic analogies
… considers a numerical approach to identifying noise mechanisms in tandem cylinders to understand aircraft landing gear as a primary contributor to airframe noise during approach and landing. Fluctuations in the flow properties induced by turbulence are computed as well as the corresponding …
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The Computation of Exact Green's Functions in Acoustic Analogy By a Spectral Collocation Boundary Element Method
<p>Aircraft airframe noise pollution resulting from the take-off and landing of airplanes is a growing concern. Because of advances in numerical analysis and computer technology, most of the current noise prediction methods are computationally efficient. However, the ability to effectively apply an …
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Effect of Boundary-Layer Tripping on Turbulence Generation and Trailing-Edge Noise in Transitional Airfoils
… focus here on attempting to directly predict the noise associated with airframe by considering a single isolated airfoil. Developing an ability to directly predict the radiated noise and how it is generated is a first step for passive or active control of the generated noise. We choose herein a …
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Impact of Liquefied Natural Gas usage and payload size on Hybrid Wing Body aircraft fuel efficiency
… were optimized for reduced fuel burn and airframe noise at approach, based on NASA N+3 goals for the 2030 timeframe. Well-to-wake greenhouse gas emissions for LNG from conventional sources were estimated to be 16% lower than conventional Jet A. Minimally insulated in-wing storage was shown …
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Physics-based aeroacoustic modelling of bluff-bodies
… this work physics-based modelling of bluff-body noise was performed with application to landing gear noise production. The landing gear is a primary contributor to airframe noise during approach. Noise is primarily generated from the unsteady pressures resulting from the turbulent flow around …
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Modeling performance and noise of advanced operational procedures for current and future aircraft
Increasing concerns regarding aircraft noise has encouraged the push to reduce noise via operational adjustments. The objective here is thus to expand analysis capabilities to enable modeling of the impact on aircraft noise due to advanced operational approach procedures, such as delayed …
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Aerodynamics and aeroacoustics of flap side-edges
… to the flap side-edge in an attempt to reduce airframe noise. Measurements taken as part of the experimental study were forces, on-surface pressures, particle image velocimetry, hotwire anemometry and on-surface microphones. Oil flow was performed to visualise the on-surface flow. A detached …
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Acoustic Scattering in Sheared Flow
Airframe noise, the noise of an aircraft in flight not due to the engine or other mechanical devices, is often a major contribution to the sound heard from an aircraft during landing approach. Over the past few decades certification requirements have gradually tightened, reaching the point where …
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Scattering by porous aerofoil adaptations
… in particular, can generate a large amount of noise that causes disruption and irritation. From the beginning of the jet era, the need to control aeroacoustic noise generation has been important in order to minimise the environmental impact of the aviation industry and its expansion. Sharp …
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Numerical investigation of slat noise attenuation using acoustic liners
Noise generated by high-lift devices such as slats on a wing is a major contributor to the overall airframe noise during the landing approach of a commercial aircraft. In this work the concept of attenuating slat noise using absorptive acoustic liners in the slat/main element gap is explored using …