1 edition of Acoustic source and data acquisition system for a helicopter rotor blade-vortex interaction (BVI) noise reduction experiment found in the catalog.
by Naval Postgraduate School, Available from National Technical Information Service in Monterey, Calif, Springfield, Va
Written in English
One of the most objectional noises produced by a helicopter is due to interaction of a rotor blade with a previously shed vortex. Various methods have been proposed to reduce this blade/vortex interaction (BVI) noise; this investigation is concerned with BVI noise reduction by rotor blade tip design modifications. Potentially much can be learned regarding the prospect for success of a candidate rotor blade design at greatly reduced time and money by performing acoustic scattering measurements in an anechoic chamber. It is proposed that a rotor blade which scatters acoustic waves less could be expected to produce less BVI noise. This thesis describes the development of the acoustic source and computer controlled data acquisition system for such a scattering experiment.
|Statement||Brian D. Roth|
|The Physical Object|
|Pagination||xi, 62 p. ;|
|Number of Pages||62|
rotor congurations determined is carried out in order to examine the impact of low-vibration blade design on the emitted noise eld. 1. Introduction Main rotors play a fundamental role in helicopter dynamics, providing both li ing force and thrust, but, as a by-product, they are sources of . CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): A great deal of progress has been made in the modeling of aerodynamically generated sound of rotors over the past decade. Although the modeling effort has focused on helicopter main rotors, the theory is generally valid for a wide range of rotor configurations. The Ffowcs Williams--Hawkings (FW-H) equation has been.
An advantage of the current dataset is that direct near-field acoustic data is made available and this allows easy and direct comparisons with CFD predictions, without the need to use far-field aeroacoustic methods. 1. Introduction Reduction of helicopter rotor noise is an important objective for design engineers aiming to achieve certification of. large blade tip amplitude for rotor noise reduction is going on. In terms of noise reduction, these active techniques are efficient for Blade/Vortex Interaction (BVI) noise which is generated during the approach to the landing area and occupies a large part of an issue for the public acceptance of helicopter.
Duplicate Title to Helicopter tail rotor orthogonal blade vortex interaction User Workarea, Mr Adam Field - [ Manage ] [ Compare & Merge ] [ Acknowledge ] The aerodynamic operating environment of the helicopter is particularly complex and, to some extent, dominated by the . Vibration Reduction and Performance Enhancement of Helicopter Rotors Using an Active/Passive Approach the dominant source of vibration is the rotor, which transfers vibratory loads to the rotor for locating reduced vibration designs at low advance ratios in which blade-vortex interaction (BVI).
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Acoustic Source and Data Acquisition System for a Helicopter Rotor Blade-Vortex Interaction (BVI) Noise Reduction Experiment [Brian D. Roth] on *FREE* shipping on qualifying offers. This is a NAVAL POSTGRADUATE SCHOOL MONTEREY CA report procured by the Pentagon and made available for public release.
It has been reproduced in the best form available to the Pentagon. helicopter tail rotor and main rotor tip vortices, we developed a two-step approach. In the first step, the main rotor tip vortex system is obtained through a free wake geometry calculation of the main rotor using CAMRAD code developed by Johnson.
This allows us to define each individual tail. maneuvering longitudinal flight, is implemented for helicopter main rotor Blade-Vortex Interaction (BVI) noise.
Various approach trajectories are formulated and analytical estimates of the BVI noise radiation characteristics associated with a full-scale two-bladed rotor are mapped to the ground using this quasi-static mapping approach. A New Experimental Approach to Study Helicopter Blade-Vortex Interaction Noise by Sudarshan N.
Koushik Dissertation submitted to the Faculty of the Graduate School of the University of Maryland, College Park in partial fulﬁllment of the requirements for the degree of Doctor of Philosophy Advisory Commmittee: Professor Fredric H.
Schmitz. acoustic data and an acoustic triangulation tech- nique to identify the location in the rotor disk where blade-vortex interaction occurred. The triangula- tion was used successfully in reference 7 on acoustic data acquired from a four-bladed rotor system and again in reference 8 on another four-bladed rotor sys.
Acoustic data taken in the anechoic Deutsch-Niederlaendischer Windkanal (DNW) have documented the blade-vortex interaction (BVI) impulsive noise radiated from a 1/7-scale model main rotor of the. Introduction.
Helicopter impulsive noise is generated from two distinct aerodynamic events. One is from compressible flow field due to high tip Mach numbers on the rotor's advancing side, called high-speed impulsive noise, and the second type is from unsteady pressure fluctuations on a rotor blade due to interactions with vortices generated by previous blades, called blade–vortex Cited by: Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover Article in International Journal of Numerical Methods for Heat and Fluid Flow 26(7) September with.
Helicopter Blade-Vortex Interaction Noise with Comparisons to CFD Calculations MEGAN S MCCLUER Ames Research Center Summary A comparison of experimental acoustics data and computational predictions was performed for a helicopter rotor blade interacting with a parallel vortex.
The experi-ment was designed to examine the aerodynamics and. Full text of "Helicopter tail rotor blade-vortex interaction noise" See other formats NASA Contractor Report ^, _^ Helicopter Tail Rotor Blade-Vortex Interaction Noise Albert R.
George and S.-T. Chou Sibley School of Mechanical and Aerospace Engineering Upson and Grumman Halls Cornell University Ithaca, New York (**S1-CB) BELICCPfEE lill ECIOB N EiAD£-¥CBIEX INIIfiCTICS «C1. Helicopter noise reduction is a topic of research into designing helicopters which can be operated more quietly, reducing the public-relations problems with night-flying or expanding an airport.
In addition, it is useful for military applications in which stealth is required: long-range propagation of helicopter noise can alert an enemy to an incoming helicopter in time to re-orient defenses. AN EXPERIMENTAL STUDY OF PARALLEL BLADE-VORTEX INTERACTION AERODYNAMICS AND ACOUSTICS UTILIZING AN INDEPENDENTLY GENERATED VORTEX C.
Kitaplioglu, F. Caradonna, and M. McCluer Ames Research Center SUMMARY This report presents results from an experimental study of rotor blade-vortex interaction (BVI) aerodynamics and acoustics. Into the Physics of Rotor Aeroacoustics - Highlights of recent European Helicopter Noise Research of advanced acoustic-data acquisition systems for the radiated noise, of sophisticated flow visualisation and flow measurement tech- vortex characteristics especially at conditions of blade vortex interaction, the,Projected Grid.
2 Helicopter noise sources and related noise generation mechanisms Rotor noise The general principles of rotor noise generation mechanisms are well summarized in the CAEP/5 HTTG4 HELO-2 Task Group DATA REPORT to WG1 – Technology Status on Helicopter Noise Stringency updated in and for simplicity summarized Size: 2MB.
Brian D. Roth has written: 'Acoustic source and data acquisition system for a helicopter rotor blade-vortex interaction (BVI) noise reduction experiment' Asked in English to Scottish Gaelic and.
Helicopter Tail Rotor Orthogonal Blade Vortex Interaction When a vortex passes close to or impacts with a helicopter rotor blade, the event is termed a Blade Vortex Interaction (BVI). Tail rotor BVIs occur for a wide range of reducing acoustic emissions.
For example, when a Westland Lynx was fitted with a. Schematic of rotor blade trailing edge flap actuated by extension-torsion coupled composite tube and magnetostrictive Reduction of helicopter blade--vortex interaction noise leverage system where considerable performance losses took place, especially at higher rotational speeds.~2) A better concept was investigated where a Cited by: blade-vortex interaction (BVI) noise is a relatively new ﬁeld for computational research.
Two structural models are considered for the present study; the ﬁrst is a modal approach suitable for four-bladed hin-geless rotors. The second is a ﬁnite element approach that is used to consider a ﬁve-bladed bearingless rotor.
helicopter flight simulation. The rotor grid, consisting of 2 blades for main-rotor and 4 blades for tail-rotor, communicates with inner-/outer-background grids during unsteady computations. The Blade-Vortex Interaction (BVI) noise of main-rotor and tail-rotor noise are predicted using a combination method of an.
Modern helicopters still suffer from many problems that hinder a further increase in their efficiency, acceptance and hence their market share. The high level of vibrations and the noise generated by the rotor are the most important reasons for this.
Vibrations are problematic not only for pilot and passenger comfort, but also give rise to an increase in maintenance by:. Fundamental Research in Helicopter Rotor Blade - Vortex Interaction Modeling D.R. Poling, Boeing Helicopters, M.C.
Wilder, D.P. Telionis, Virginia Polytechnic Institute May 6, Your Path: Home > Fundamental Research in Helicopter Rotor Blade - Vortex Interaction ModelingCited by: 2.Two initial “demonstrators” are designed to deliver aerodynamic performance (Aero-H) and aero-acoustic data (Aku-H) for the High-Speed Impulsive (HSI) noise generated by the two-bladed model of a helicopter rotor in high-speed, transonic hover by: 3.The BVI (Blade Vortex Interaction) phenomenon,especially parallel interactions between the helicopter main rotor blade and the tip vortex, is the cause of significant noise and vibration problems in helicopter operation.
In particular, the descent and banked turn flight .