Correction: Perceived Noise Assessment of Offset Three-Stream Nozzles for Low Noise Supersonic Aircraft

2018 ◽  
Author(s):  
Dimitri Papamoschou ◽  
Vincent C. Phong
Keyword(s):  
Low Noise ◽  
Supersonic Aircraft ◽  
Noise Assessment

scholarly journals Guidelines for the LTO Noise Assessment of Future Civil Supersonic Aircraft in Conceptual Design

Aerospace ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Grazia Piccirillo ◽  
Nicole Viola ◽  
Roberta Fusaro ◽  
Luigi Federico
Keyword(s):  
Conceptual Design ◽  
Aircraft Design ◽  
Low Noise ◽  
Aircraft Noise ◽  
Noise Model ◽  
Noise Power ◽  
Community Noise ◽  
Prediction Program ◽  
Supersonic Aircraft ◽  
Noise Assessment

One of the most critical regulatory issues related to supersonic flight arises from limitations imposed by community noise acceptability. The most efficient way to ensure that future supersonic aircraft will meet low-noise requirements is the verification of noise emissions from the early stages of the design process. Therefore, this paper suggests guidelines for the Landing and Take-Off (LTO) noise assessment of future civil supersonic aircraft in conceptual design. The supersonic aircraft noise model is based on the semi-empirical equations employed in the early versions of the Aircraft NOise Prediction Program (ANOPP) developed by NASA, whereas sound attenuation due to atmospheric absorption has been considered in accordance with SAE ARP 866 B. The simulation of the trajectory leads to the prediction of the aircraft noise level on ground in terms of several acoustic metrics (LAmax, SEL, PNLTM and EPNL). Therefore, a dedicated validation has been performed, selecting the only available supersonic aircraft of the Aircraft Noise and Performance database (ANP), that is, the Concorde, through the matching with Noise Power Distance (NPD) curves for LAmax and SEL, obtaining a maximum prediction error of ±2.19%. At least, an application to departure and approach procedures is reported to verify the first noise estimations with current noise requirements defined by ICAO at the three certification measurement points (sideline, flyover, approach) and to draw preliminary considerations for future low-noise supersonic aircraft design.

EPISTLE: High lift system design for low-noise applied to a supersonic aircraft

2006 ◽  
Vol 110 (1107) ◽  
pp. 327-331 ◽  
Author(s):  
U. Herrmann
Keyword(s):  
System Design ◽  
Aircraft Design ◽  
Reynolds Numbers ◽  
Low Noise ◽  
High Lift ◽  
New Approach ◽  
Low Speed ◽  
Supersonic Aircraft ◽  
Preliminary Aircraft Design ◽  
High Reynolds

Abstract A new approach for low-drag high-lift system design based on the application of viscous flow solvers was developed in the EC research project EPISTLE. Two high-lift systems for a supersonic commercial transport aircraft (SCT) wing were designed, manufactured and wind-tunnel tested. The predicted large drag reductions were fully confirmed by tests at high Reynolds numbers. These drag reductions significantly reduce the low-speed noise of future SCT configurations. This was estimated by preliminary aircraft design tools. Low-speed noise reduction by aerodynamic means is obtained, as effective high-lift systems enable these aircraft to climb faster.

Noise predictions for a supersonic business jet using advanced take-off procedures

2018 ◽  
Vol 122 (1250) ◽  
pp. 556-571 ◽  
Author(s):  
J. J. Berton ◽  
S. M. Jones ◽  
J. A. Seidel ◽  
D. L. Huff
Keyword(s):  
Jet Noise ◽  
Analytical Models ◽  
Noise Levels ◽  
Engine Exhaust ◽  
Supersonic Aircraft ◽  
Business Jet ◽  
Civil Aircraft ◽  
Noise Assessment ◽  
The Subject ◽  
Specific Thrust

ABSTRACTSupersonic civil aircraft present a unique noise certification challenge. High specific thrust required for supersonic cruise results in high engine exhaust velocity and high levels of jet noise during take-off. Aerodynamics of thin, low-aspect-ratio wings equipped with relatively simple flap systems deepen the challenge. Advanced noise reduction procedures have been proposed for supersonic aircraft. These procedures promise to reduce certification noise levels, but they may require departures from normal reference procedures defined in noise regulations. The subject of this article is a take-off performance and noise assessment of a notional supersonic business jet. Analytical models of an airframe and a supersonic engine derived from a contemporary subsonic turbofan core are developed. These models are used to predict take-off trajectories and certification noise levels. Results indicate advanced take-off procedures are helpful in reducing noise along lateral sidelines.

A Hybrid and Efficient Low-noise assessment Platform for Urban aerial mobility (HELPU)

2021 ◽  
Vol 263 (3) ◽  
pp. 3756-3768
Author(s):  
Siyang Zhong ◽  
Peng Zhou ◽  
Yi Fang ◽  
Xin Zhang
Keyword(s):  
Prediction Models ◽  
Noise Pollution ◽  
Control Device ◽  
Low Noise ◽  
Long Distance ◽  
Flight Planning ◽  
High Efficient ◽  
Noise Assessment ◽  
Complex Boundary ◽  
The Impact

Urban aerial mobility (UAM) is a promising approach to improve the traffic situation in gigantic cities, which, however, may encounter significant noise pollution issues. An integrated research platform, which is being established at HKUST, to include noise generation, long-distance propagation, and perception at the observers is timely to assess the environmental impact of UAM noise and to develop low-noise designs and flight planning. A high-quality test rig in the anechoic aerodynamic facility at HKUST is employed to measure the propeller aeroacoustics and aerodynamics, and to enable the innovative noise control device and design studies. The measurements and high-fidelity simulations using an in-house computational aeroacoustics solver can lead to comprehensive databases to facilitate and validate the development of physics-oriented noise prediction models. Also, high-efficient implementation of the boundary element method is conducted to account for the noise scattering due to the fuselage and then to evaluate the impact of UAM layout on the directivity patterns, which will then be efficiently projected to the far-field observers using the advanced Gaussian beam tracing with the effects due to moving source, atmospheric attenuation, and refraction, complex boundary absorption and reflection incorporated. Low-noise flight planning is then be made accordingly.

scholarly journals System Noise Assessment and the Potential for Low Noise Hybrid Wing Body Aircraft with Open Rotor Propulsion

2014 ◽  
Author(s):  
Russell H. Thomas ◽  
Casey L. Burley ◽  
Leonard V. Lopes ◽  
Christopher J. Bahr ◽  
Frank H. Gern ◽  
...  
Keyword(s):  
Low Noise ◽  
System Noise ◽  
Open Rotor ◽  
Noise Assessment

scholarly journals Tonal-Noise Assessment of Quadrotor-Type UAV Using Source-Mode Expansions

Acoustics ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 674-690
Author(s):  
Michel Roger ◽  
Stéphane Moreau
Keyword(s):  
Ad Hoc ◽  
Sound Field ◽  
Low Noise ◽  
Urban Traffic ◽  
Mean Flow ◽  
Forward Flight ◽  
Aerodynamic Sound ◽  
Fast Running ◽  
Noise Assessment ◽  
Low Noise Design

The present work deals with the modeling of the aerodynamic sound generated by the propellers of small-size drones, taking into account the effects of horizontal forward flight with negative pitch and of installation on supporting struts. Analytical aeroacoustic formulations are used, dedicated to the loading noise. The fluctuating lift forces on the blades are expanded as circular distributions of acoustic dipoles, the radiated field of which is calculated by using the free-space Green’s function. This provides descriptions of the sound field, valid in the entire space. The stationary mean-flow distortions responsible for the lift fluctuations and at the origin of the sound are estimated from existing numerical flow simulations and from ad hoc models. Installation and forward-flight effects are found to generate much more sound than the steady loading on the blades associated with thrust. Therefore, the models are believed reliable fast-running tools that could be used for preliminary low-noise design through repeated parametric calculations, or for noise-impact estimates corresponding to prescribed urban traffic.

scholarly journals Aircraft noise in residential areas, problems of measuring and evaluation

2020 ◽  
Vol 99 (10) ◽  
pp. 1042-1048
Author(s):  
Igor V. Bukhtiyarov ◽  
Nicolay N. Courierov ◽  
Alla V. Lagutina ◽  
Lyudmila V. Prokopenko ◽  
Evgeny V. Zibarev
Keyword(s):  
Low Noise ◽  
Aircraft Noise ◽  
Time Interval ◽  
Residential Areas ◽  
Reference Time ◽  
Sound Levels ◽  
Sound Event ◽  
Noise Assessment ◽  
Normalized Parameters ◽  
Definition Of

The intensity of civil aircraft flights elevates with the increase in the number of passenger and cargo transportation by air. Aircraft noise in the residential area near airports grows up too despite the use of low-noise aircraft models by airlines. This causes an augmentation in the number of complaints of the population in these areas. The Russian Federation’s normative and methodological documents requirements in force relating to measurements and assessment of noise in residential areas, including «aircraft noise», were analyzed. Their requirements in terms of measuring and assessing noise in residential areas, including “aircraft noise”, testifies to the insufficiency and ambiguity of these requirements. The main disadvantages are the lack of a clear definition of which sound event is considered «aircraft noise» and the lack of requirements for the duration of the reference time interval of noise measurement. The foreign experience of measuring and evaluating aircraft noise, as well as the effects of such noise on the population, are considered. This made it possible to determine the necessary and sufficient parameters for noise control in residential areas, including «aircraft noise». There were proposed both a definition of «aircraft noise» and the necessary parameters for its assessment. The necessary duration of the reference time interval for the measurement of normalized parameters was justified. Method for the normalized noise parameters in residential areas measurement using the chronograms of sound levels A was proposed. The technical implementation of such a method is presented. Proposed a definition of «aircraft noise» and measuring normalized parameters in the 15-minute reference time interval for inclusion in regulatory and methodological documents will help to eliminate ambiguity in measurements and noise assessment in residential areas.

Distribution of R- and S-Process Elements in the Galactic Halo

1988 ◽  
Vol 132 ◽  
pp. 501-506
Author(s):  
C. Sneden ◽  
C. A. Pilachowski ◽  
K. K. Gilroy ◽  
J. J. Cowan
Keyword(s):  
Heavy Element ◽  
Galactic Halo ◽  
Low Noise ◽  
Heavy Elements ◽  
Process Synthesis ◽  
Element Abundances ◽  
Halo Stars ◽  
Abundance Patterns ◽  
R Process ◽  
Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

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