The Experts below are selected from a list of 1758 Experts worldwide ranked by ideXlab platform
D P Rhodes - One of the best experts on this subject based on the ideXlab platform.
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OPTIONS FOR AIRPORT APPROACH Noise CONTROL: FLIGHT PROCEDURES, AIRCRAFT Certification, AND AIRPORT RESTRICTIONS
1999Co-Authors: Robert E. Caves, A D Kershaw, D P RhodesAbstract:The use of larger aircraft and high-bypass engines has made the approach Noise at airports more critical, but the methods used to control it rely on rather tenuous relationships between aircraft Noise Certification and the Noise experienced by the communities around airports. Also, the options for alleviating approach Noise are perceived to be fewer than for the takeoff case. The effect of a variety of possible approach flight procedures is explored. All of these procedures terminate in a conventional 3-degree final glide path, on the maximum Noise levels under the flight path. In comparison, the effect of varying the glideslope angle on Noise at the approach Certification point is reported. It is concluded that the most promising procedures for alleviating Noise in the areas some distance from an airport are the Continuous Descent and the Decelerating approaches. The current use of these techniques is limited by the incompatibility with air traffic control procedures. The more severe Noise levels closer ...
Robert E. Caves - One of the best experts on this subject based on the ideXlab platform.
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OPTIONS FOR AIRPORT APPROACH Noise CONTROL: FLIGHT PROCEDURES, AIRCRAFT Certification, AND AIRPORT RESTRICTIONS
1999Co-Authors: Robert E. Caves, A D Kershaw, D P RhodesAbstract:The use of larger aircraft and high-bypass engines has made the approach Noise at airports more critical, but the methods used to control it rely on rather tenuous relationships between aircraft Noise Certification and the Noise experienced by the communities around airports. Also, the options for alleviating approach Noise are perceived to be fewer than for the takeoff case. The effect of a variety of possible approach flight procedures is explored. All of these procedures terminate in a conventional 3-degree final glide path, on the maximum Noise levels under the flight path. In comparison, the effect of varying the glideslope angle on Noise at the approach Certification point is reported. It is concluded that the most promising procedures for alleviating Noise in the areas some distance from an airport are the Continuous Descent and the Decelerating approaches. The current use of these techniques is limited by the incompatibility with air traffic control procedures. The more severe Noise levels closer ...
Simons D.g. - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the sound quality of wind turbine Noise reduction measures
2019Co-Authors: Merino Martinez R., Pieren R.d., Snellen M., Simons D.g.Abstract:Noise emissions from wind turbines are one of the main issues that the wind energy industry must deal with nowadays. Strict Noise regulations often prevent wind turbines to operate at maximum power conditions, causing large losses of power production and, hence, of revenue. Several Noise reduction measures have been proposed so far, but the use of trailing-edge serrations and permeable inserts seem to be the two most promising approaches, showing broadband Noise reductions of several decibels. This paper considers the Noise reductions (with respect to the baseline blade) observed in previous wind-tunnel measurements featuring these two measures, and scales and synthetically applies them to an experimental recording of a full-scale Vestas V90-2.0 MW wind turbine in operational conditions. The calculated results are then auralized for the observer location used for Noise Certification in the IEC 61400-11 standard. State-of-the-art sound quality metrics (loudness, tonality, sharpness, roughness and fluctuating strength) are then applied to these simulated sound signals to better understand the achieved reduction in Noise annoyance experienced by humans. Reductions in the maximum A-weighted sound pressure level (Lp,A,max) of about 2.4 and 1.2 dBA are observed for the serrations and permeable inserts, respectively. In general, trailing-edge serrations seem to reduce the calculated annoyance experienced (17% lower than the baseline) more efficiently than the permeable inserts (just 2% lower)
A D Kershaw - One of the best experts on this subject based on the ideXlab platform.
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OPTIONS FOR AIRPORT APPROACH Noise CONTROL: FLIGHT PROCEDURES, AIRCRAFT Certification, AND AIRPORT RESTRICTIONS
1999Co-Authors: Robert E. Caves, A D Kershaw, D P RhodesAbstract:The use of larger aircraft and high-bypass engines has made the approach Noise at airports more critical, but the methods used to control it rely on rather tenuous relationships between aircraft Noise Certification and the Noise experienced by the communities around airports. Also, the options for alleviating approach Noise are perceived to be fewer than for the takeoff case. The effect of a variety of possible approach flight procedures is explored. All of these procedures terminate in a conventional 3-degree final glide path, on the maximum Noise levels under the flight path. In comparison, the effect of varying the glideslope angle on Noise at the approach Certification point is reported. It is concluded that the most promising procedures for alleviating Noise in the areas some distance from an airport are the Continuous Descent and the Decelerating approaches. The current use of these techniques is limited by the incompatibility with air traffic control procedures. The more severe Noise levels closer ...
Christopher J Roof - One of the best experts on this subject based on the ideXlab platform.
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development of simplified procedure for computing the absorption of sound by the atmosphere and applicability to aircraft Noise Certification proposed sae method
2012Co-Authors: Edward J Rickley, Gregg G Fleming, Christopher J Roof, Joyce E Rosenbaum, Eric R BoekerAbstract:This report presents the results of the study to extend the useful attenuation range of the Approximate Method outlined in the American National Standard, “Method for Calculation of the Absorption of Sound by the Atmosphere” (ANSI S1.26-1995), and provide a basis for replacing the current Society of Automotive Engineers Aerospace Recommended Practice 866A, “Standard Values of Atmospheric Absorption as a Function of Temperature and Humidity” (SAE ARP 866A). The report describes the implementation of the one-third octave-band adaptations of the ISO/ANSI pure-tone equations, and the development and testing of the proposed SAE Method.
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validation protocol for digital audio recorders used in aircraft Noise Certification testing
2010Co-Authors: Robert Samiljan, Gregg G Fleming, David R Read, Christopher J RoofAbstract:The U.S. Department of Transportation, Research and Innovative Technology Administration, John A. Volpe National Transportation Systems Center, Environmental Measurement and Modeling Division (Volpe), is supporting the aircraft Noise Certification initiatives of the Federal Aviation Administration (FAA), Office of Environment and Energy (AEE) by preparing the “Validation Protocol for Digital Audio Recorders Used in Air-craft-Noise-Certification Testing” (Validation Protocol). As analog and digital tape-based recording devices are becoming obsolete, this Validation Protocol has been developed for applicants requesting permission from FAA/AEE to conduct aircraft Noise Certification testing using non-tape-based recorders. Because of the significant differences between non-tape-based recording devices and all preceding technologies, this Protocol establishes a set of procedures for testing and evaluating the performance of non-tape-based digital audio recorders proposed for aircraft Noise Certification use. If using any of the digital audio recording devices covered by the scope of this document, it is recommended that an applicant perform tests to evaluate the characteristics of the re-cording device in accordance with the guidance in the Validation Protocol to demonstrate compliance with part 36 Title 14 of the Code of Federal Regulations (Part 36) and Inter-national Civil Aviation Organization Annex 16 Volume I (ICAO Annex 16).
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a differential global positioning system for determining time space position information in support of aircraft Noise Certification
2001Co-Authors: Gregg G Fleming, Christopher J Roof, Joseph Ruggiero, Michael Geyer, Brian Kim, Thomas L Connor, James SkaleckyAbstract:Federal Aviation Regulation (FAR) Part 36, Noise Standards: Aircraft Type and Airworthiness Certification, requires that measured aircraft Noise Certification data be corrected to a nominal reference-day condition. This correction process which can be quite rigorous is typically done for sequential 1⁄2-second acoustic data records measured for a given aircraft Noise Certification event. Consequently, the process requires precise time-space-position-information (TSPI) for each acoustic data record within each event. Traditionally, Noise Certification applicants have used optical positioning systems such as still cameras and video 10 cameras, radar, or in rare instances, laser tracking systems. The accuracy of these systems is typically on the order of 10 to 20 ft., although the accuracy of laser tracking systems can be much better. In addition, many of these traditional systems only provide TSPI data over a relatively limited time interval in the vicinity of aircraft overhead, thus requiring extrapolation of TSPI data to sufficiently define aircraft position for each acoustic data record within each Certification event. With the advent of differentially corrected global positioning systems (dGPS), the accuracy and limitations associated with traditional TSPI systems are easily overcome. This paper describes a dGPS TSPI system developed by the U.S. Department of Transportation (DOT) Volpe Center Acoustics Facility (Volpe). The paper includes descriptions of both the hardware and software components of the system. It also details the static and dynamic system performance.