Rotorcraft Noise PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Rotorcraft Noise PDF full book. Access full book title Rotorcraft Noise by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 454
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 454
Get Book Here
Book Description
Author: Interagency Aircraft Noise Research Panel
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 232
Get Book Here
Book Description
Author: Harvey H. Hubbard
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 616
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 42
Get Book Here
Book Description
Author: William C. Sperry
Publisher:
ISBN:
Category : Airport noise
Languages : en
Pages : 64
Get Book Here
Book Description
Author: Willca Villafana
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
A rotorcraft noise prediction system has recently been developed as part of aproject to develop and evaluate helicopter noise abatement procedures for a rangeof aircraft. The aim of this thesis is to demonstrate the noise prediction systemcapabilities and then consider simple noise abatement procedures for three differenthelicopters of varying technology levels and maximum gross weights.First, the codes that have been assembled into the noise prediction system aredescribed. A brief presentation of acoustic theory on which the noise prediction isbased is given as a reminder. Then, the noise prediction system has been validatedwith the Bell 430 helicopter flying in a level forward flight. The prediction systemhas also demonstrated its capacity to predict blade vortex interaction (BVI) noiseand BVI noise reduction. Finally several abatement procedures have been examined.The two first ones underscored the benefits of flying higher and slower by usingthe S-76C+ as an example. Then, a S-76C+, Bell 430 and BK 117 helicopterswere compared in a level forward flight. The comparison ended up with surprisingresults about loading and broadband noise since they do not appear correlated tothe weight of the rotorcrafts. Yet, thickness noise results are expected since theyare related to the rotor tip speeds. Finally, the effects of descent angle and speedon BVI noise have been demonstrated during approach. A Bell 430 helicopter wasused for this study and the speed and angle of descent were varied separately whilekeeping all the other parameters constant.
Author: F. H. Schmitz
Publisher:
ISBN:
Category :
Languages : en
Pages : 110
Get Book Here
Book Description
The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.
Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781723974762
Category : Science
Languages : en
Pages : 80
Get Book Here
Book Description
This report addresses development of a rotor state/trim modeling capability for noise modeling of decelerating rotorcraft approaches. The resulting technique employs discretization of the descent trajectory as multiple steady state segments for input to CAMRAD.Mod 1 to predict rotor states for acoustic analysis. Deceleration is included by modifying the CAMRAD.Mod 1 free flight trim options to allow trim to the specified acceleration/deceleration components.Murty, Hema and Berezin, Charles R.Langley Research CenterNOISE REDUCTION; FLIGHT PATHS; APPLICATIONS PROGRAMS (COMPUTERS); MATHEMATICAL MODELS; SIKORSKY WHIRLWIND HELICOPTER; FLIGHT TESTS; STEADY STATE; ACOUSTIC MEASUREMENT; DESCENT TRAJECTORIES; DECELERATION
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722748340
Category :
Languages : en
Pages : 28
Get Book Here
Book Description
This paper briefly reviews rotorcraft noise mechanisms and their approximate importance for different types of rotorcraft in different flight regimes. Discrete noise is due to periodic flow disturbances and includes impulsive noise produced by phenomena which occur during a limited segment of a blade's rotation. Broadband noise results when rotors interact with random disturbances, such as turbulence, which can originate in a variety of sources. The status of analysis techniques for these mechanisms are reviewed. Also, some recent progress is presented on the understanding and analysis of tilt rotor aircraft noise due to: (1) recirculation and blockage effects of the rotor flow in hover; and (2) blade-vortex interactions in forward and descending flight. George, Albert R. and Sim, Ben WEL-C. and Polak, David R. Unspecified Center NAG2-554...
Author: Juan Abelló
Publisher:
ISBN:
Category :
Languages : en
Pages : 466
Get Book Here
Book Description
