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.

Effects of Increased Noise Levels by Supersonic Aircraft on Annoyance Levels and Time Estimations

1980 ◽  
Vol 50 (2) ◽  
pp. 563-569
Author(s):  
John A. Allen
Keyword(s):  
Aircraft Noise ◽  
Noise Levels ◽  
Supersonic Aircraft ◽  
International Airport

Several tests designed to assess the effects of increased noise levels created by the Concorde supersonic aircraft were administered to 48 residents living around Dulles International Airport and 31 persons not living near an airport. Results of a pretest questionnaire and lack of significant changes in annoyance levels and time estimations indicate that, while airport-area residents may be more conscious of aircraft noise, changes in the perceived intensities of sounds may not occur.

Station facilities and noise assessment: A multilevel analysis on light rail train stations

2021 ◽  
Vol 69 (4) ◽  
pp. 364-372
Author(s):  
Yalcin Yildirim ◽  
Diane Jones Allen
Keyword(s):  
Public Transportation ◽  
Transportation Systems ◽  
Urban Life ◽  
Light Rail ◽  
Noise Levels ◽  
Transit Systems ◽  
Message Boards ◽  
Sound Levels ◽  
Noise Assessment ◽  
Ticket Vending Machines

Noise is one of the most frequent consequences of traffic. Public transportation systems, such as the Dallas Area Rapid Transit (DART) authority provides various modes of transportation. Even though the availability of commuting service for the public is a boon to communities, mass transit systems are potential sources of excessive sound levels in daily urban life. This article examines the nexus between the transit station facilities of light rail train (LRT) stations and noise implications at both station and neighborhood scales by studying selected LRT stations. A multilevel linear analysis was conducted to understand the degree of train station amenities and neighborhood characteristics that affect sound levels. Using a type II sound pressure level (SPL)meter, sound measurements were obtained during the weekdays and weekends over several weeks. Upon examining the station amenities, and built environment and sociodemographic characteristics of the neighborhood, findings of this comprehensive research reveal significant implications for sound levels. Stations with ticket vending machines and informative message boards include a higher degree of significance on SPLs, while shelters, crew rooms, bike lockers, restrooms, and windshields are significantly and negatively associated with the noise levels. Additionally, neighborhoods with dense roads, higher speed limits, more neighborhood facilities, and a higher number of transit routes have an increased likelihood of noise levels. Recommendations include creating transformative policies for implementation, and approaches addressing noise for transit authorities, transportation engineers, and planners are presented. Planning and engineering aspects of comfort, aesthetics, safety, and public health, as train stations are daily use spaces for commuters and surrounding communities, should also be considered.

Noise Propagation Through Helicopter Gearbox Support Struts—An Experimental Study

1998 ◽  
Vol 120 (3) ◽  
pp. 695-704 ◽  
Author(s):  
M. J. Brennan ◽  
S. J. Elliott ◽  
K. H. Heron
Keyword(s):  
Experimental Study ◽  
Kinetic Energy ◽  
Flexural Vibration ◽  
Dominant Mode ◽  
Analytical Models ◽  
Longitudinal Motion ◽  
Transmission Path ◽  
Modes Of Vibration ◽  
The Subject ◽  
Lateral Behavior

A dominant source of noise in a helicopter cabin is the meshing of the gears in the main rotor gearbox. The main structural noise transmission path from this gearbox to the cabin is through the gearbox support struts, and this is the transmission path which is the subject of this paper. An experimental study is described which quantifies the way in which vibration propagates through one of these struts and the experimental results are interpreted with the aid of some simple analytical models. The contribution of the various modes of vibration to the transmission of the structure-borne noise is quantified by calculating the kinetic energy of the receiving structure from measured data. The results show that although the dominant mode of vibration is longitudinal, flexural resonances occur at some frequencies, and the contribution of the flexural vibration to the kinetic energy of the receiving structure at these frequencies can be comparable with that due to the longitudinal motion. It is demonstrated that the lateral behavior of the strut is dependent upon the static loading but the longitudinal behavior is relatively insensitive to this loading.

scholarly journals Comparison of Acceptable Noise Level Generated Using Different Transducers and Response Modes

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Liang Xia ◽  
Jingchun He ◽  
Yuanyuan Sun ◽  
Yi Chen ◽  
Qiong Luo ◽  
...  
Keyword(s):  
Noise Level ◽  
Sound Field ◽  
Normal Hearing ◽  
Noise Levels ◽  
Presentation Modes ◽  
Significant Difference ◽  
Acceptable Noise Level ◽  
The Subject ◽  
Response Modes ◽  
Chinese Subjects

The acceptable noise level (ANL) was defined by subtracting the background noise level (BNL) from the most comfortable listening level (MCL) (ANL = MCL − BNL). This study compared the ANL obtained through different methods in 20 Chinese subjects with normal hearing. ANL was tested with Mandarin speech materials using a loudspeaker or earphones, with each subject tested by himself or by the audiologist. The presentation and response modes were as follows: (1) loudspeaker with self-adjusted noise levels using audiometer controls (LS method); (2) loudspeaker with the subject signaling the audiologist to adjust speech and noise levels (LA method); (3) earphones with self-adjusted noise levels using audiometer controls (ES method); and (4) earphones with the subject signaling the audiologist to adjust speech and noise levels (EA method). ANL was calculated from three measurements with each method. There was no significant difference in the ANL obtained through different presentation modes or response modes sound. The correlations between ANL, MCL, and BNL obtained from each two methods were significant. In conclusion, the ANL in normal-hearing Mandarin listeners may not be affected by presentation modes such as a loudspeaker or earphones nor is it affected by self-adjusted or audiologist-adjusted response modes. Earphone audiometry is as reliable as sound field audiometry and provides an easy and convenient way to measure ANL.

scholarly journals Modelling performance an air transport network operated by subsonic and supersonic aircraft

2020 ◽  
Vol 124 (1281) ◽  
pp. 1702-1739
Author(s):  
M. Janić
Keyword(s):  
Social Performance ◽  
Economic Feasibility ◽  
Transport Network ◽  
Air Transport ◽  
Analytical Models ◽  
Commercial Aircraft ◽  
Supersonic Aircraft ◽  
Route Network ◽  
Fuel Consumption And Emissions ◽  
The Given

ABSTRACTThis paper deals with modelling the performance of an air transport network operated by existing subsonic and the prospective supersonic commercial aircraft. Analytical models of indicators of the infrastructural, technical/technological, operational, economic, environmental, and social performance of the network relevant for the main actors/stakeholders involved are developed. The models are applied to the given long-haul air route network exclusively operated by subsonic and supersonic aircraft according to the specified “what-if” scenarios.The results from application of the models indicate that supersonic flights powered by LH2 (Liquid Hydrogen) could be more feasible than their subsonic counterparts powered by Jet A fuel, in terms of about three times higher technical productivity, 46% smaller size of the required fleet given the frequency of a single flight per day, 20% lower sum of the aircraft/airline operational, air passenger time, and considered external costs, up to two times higher overall social-economic feasibility, and 94% greater savings in contribution to global warming and climate change. These flights could be less feasible in terms of about 70-85% higher aircraft/airline operational costs, 70% and 19% higher fuel consumption and emissions of Green House Gases, respectively, and 6-13% higher noise compared to the specified acceptable levels.

Interference Effect of Engine Exhaust on Civil Aircraft Drag Performance

2012 ◽  
Vol 49 (6) ◽  
pp. 2001-2006 ◽  
Author(s):  
Weilin Zheng ◽  
Yankui Wang ◽  
Jixiang Shan ◽  
Xueying Deng ◽  
Wei Tian
Keyword(s):  
Interference Effect ◽  
Engine Exhaust ◽  
Civil Aircraft

Esso Energy Award Lecture, 1987 - Application of aerodynamic research and development to civil aircraft wing design

1988 ◽  
Vol 416 (1850) ◽  
pp. 43-62
Keyword(s):  
Technological Progress ◽  
Computational Fluid Mechanics ◽  
Aerodynamic Design ◽  
Wing Design ◽  
High Lift ◽  
Business Jet ◽  
Civil Aircraft ◽  
Research Programmes ◽  
The Government

In the late 1950s the aerodynamicists at what is now the Hatfield site of British Aerospace accepted the challenge and met British European Airways’ demand for a 600 m. p. h. ( ca . 966 km h -1 ) short-haul jet airliner (the Trident). The experience and organization resulting from that project was the cornerstone on which the subsequent success story of civil wing design has been built. The substantial advances in efficiency achieved by the Hatfield team in the following designs for the 125 Business Jet, the 146 Feederliner and for the Airbus Industrie family of Wide-Body Mainline aircraft, has been supported by research programmes in the government establishments and universities as well as industry itself. Each project had its individual demands for fuel economy, high lift capability and structural efficiency, with commercial competition continually driving technological progress. The major highlights and achievements of the aerodynamic development programmes for these projects are reviewed. Turning to the present, the Hatfield team are currently working on the aerodynamic design for the combined Airbus A330/340 project. Technological progress continues apace with major investment in computational fluid mechanics, but the still essential role of experimental test techniques and facilities is emphasized.

Air Navigation Systems: Chapter I. Astronomical Navigation in the Air 1919–1969

1988 ◽  
Vol 41 (3) ◽  
pp. 375-406
Author(s):  
J. E. D. Williams
Keyword(s):  
Navigation Systems ◽  
Commercial Aviation ◽  
Civil Aircraft ◽  
The Subject ◽  
To Receive

This paper is the first of a series on Air Navigation Systems during the fifty years from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. These papers are intended as critical commentaries. A definitive history has yet to be written. The writer would be grateful to receive criticisms of the paper or comments on the subject.

Marine Gas Turbine Infra-Red Signature Suppression: Aerothermal Design Considerations

1989 ◽  
Author(s):  
A. M. Birk ◽  
D. Vandam
Keyword(s):  
Gas Turbine ◽  
Ambient Air ◽  
Ir Radiation ◽  
Engine Exhaust ◽  
Design Considerations ◽  
Quantitative Performance ◽  
The Subject ◽  
Ir Signature ◽  
Gas Turbine Exhaust ◽  
System Selection

In recent years it has become evident that the Infrared (IR) Radiation given off by marine gas turbine exhaust systems is highly undesirable for naval vessels and commercial vessels traveling in areas of conflict. As a result, great interest has surfaced in the ways that IR signatures can be reduced. This paper presents an overview of some of the methods that can be used for engine exhaust IR signature suppression (IRSS). The methods considered here involve only ambient air addition for metal and plume cooling. The present paper describes various IRSS systems and discusses the basic technical criteria for system selection. Basic operating principles are also described. Aerothermal design considerations are discussed and areas requiring special care during the design are highlighted. Because of the confidential nature of the subject, direct quantitative performance comparisons cannot be made.

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