Last edited by Kijin
Wednesday, July 29, 2020 | History

2 edition of Wake geometry effects on rotor blade-vortex interaction noise directivity found in the catalog.

Wake geometry effects on rotor blade-vortex interaction noise directivity

Wake geometry effects on rotor blade-vortex interaction noise directivity

  • 98 Want to read
  • 39 Currently reading

Published by National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, For sale by the National Technical Information Service] in [Washington, DC], [Springfield, Va .
Written in English

    Subjects:
  • Wakes (Aerodynamics),
  • Rotors (Helicopters) -- Aerodynamics.

  • Edition Notes

    StatementR.M. Martin ... [et al.].
    SeriesNASA technical paper -- 3015.
    ContributionsMartin, R. M. 1956-, United States. National Aeronautics and Space Administration. Scientific and Technical Information Division.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15299720M

    Nakamura, Y.: Prediction of blade/vortex interaction noise from measured blade pressure. Pa 7th European Rotorcraft and Powered Lift Aircraft Forum, Garmisch-Partenkirchen, Federal Republic of Germany, Google Scholar. Crosswinds are found to have a significant effect on Blade-Vortex Interaction (BVI) noise radiation when the helicopter is trimmed with the fuselage oriented along the inertial flight path. However, the magnitude of BVI noise remains unchanged when the pilot orients the fuselage along the aerodynamic velocity vector, “crabbing” for zero aerodynamic : Eric Greenwood, Ben W. Sim.

    A blade vortex interaction is an unsteady phenomenon of three-dimensional nature, which occurs when a rotor blade passes within a close proximity of the shed tip vortices from a previous blade. The aerodynamic interactions represent an important topic of investigation in rotorcraft research field due to the adverse influence produced on rotor noise, particularly in low speed . teractions between the rotor blades and the vortices that they produce, known as blade vortex interactions (BVIs), produce highly impulsive loads along the blade span and are a significant source of noise and vibration. The intensity and directivity of the noise generated by a helicopter is ofconsiderableimportance forbothcivil-.

    Boundary layer and wake modifications to compressor design systems: the effect of blade-to-blade flow variations on the mean flow field of a transonic rotor: final report, 01 September August / (Wright-Patterson Air Force Base, Ohio: Air Force Aero Propulsion Laboratory, Air Force Wright Aeronautical Laboratories, Air Force. Tip-path-plane Angle Effects On Rotor Blade-Vortex Interaction Noise Levels and Directivity C.L. Burley, Planning Research Corp., R.M. Martin, NASA Langley Research Center J Your Path: Home > Tip-path-plane Angle Effects On Rotor Blade-Vortex Interaction Noise Levels and DirectivityCited by: 6.


Share this book
You might also like
A funeral sermon occasiond by the death of the Reverend Mr. John Rowland

A funeral sermon occasiond by the death of the Reverend Mr. John Rowland

All Over The World.

All Over The World.

Dyehouse manual for the shift dyer.

Dyehouse manual for the shift dyer.

Autolithography

Autolithography

Fundamentals of business enterprise taxation

Fundamentals of business enterprise taxation

The governments response to the Health Select Committee report on health inequalities.

The governments response to the Health Select Committee report on health inequalities.

history of British carpets

history of British carpets

text-book of heat

text-book of heat

Aspects de la politique francais sous lancien regime.

Aspects de la politique francais sous lancien regime.

Red sanders

Red sanders

London Docklands Railway Act 1984

London Docklands Railway Act 1984

Mathematics for calculus

Mathematics for calculus

Wake geometry effects on rotor blade-vortex interaction noise directivity Download PDF EPUB FB2

Sented which show that the directionality of rotor blade-vortex interac-tion (BVI) noise is strongly dependent on the rotor advance ratio and disk attitude.

A rotor free wake analysis is used to show that the gen-eral locus of interactions on the rotor disk is also strongly dependent on advance ratio and disk attitude. A rotor free wake analysis is used to show that the general locus of interactions on the rotor disk is also strongly dependent on advance ratio and disk attitude.

A simpler approach has been investigated on noise directivity patterns using blade–vortex interaction geometry. Since a blade–vortex interaction occurs at an angle between a blade and a vortex filament, the velocity of the blade–vortex interaction point along a blade span can easily become supersonic when the interaction angle is relatively by:   On vortex–airfoil interaction noise including span-end effects, with application to open-rotor aeroacoustics Journal of Sound and Vibration, Vol.No.

1 Symmetric airfoil geometry effects on leading edge noiseCited by: Effects of tippath-plane angle and advance ratio on BVI noise are presented and compared with trends observed in previous small-scale wind tunnel and two- bladed rotor flight tests.

Limited comparisons are made with acoustic measurements acquired in the. It is shown that the magnitude and directivity of the noise is strongly dependent on the rotor wake characteristics when blade-vortex interactions occur.

In the transient arrested descent maneuver, the wake geometry becomes extremely complicated, and a significant increase in both nonimpulsive and impulsive noise is predicted.

Blade-vortex interaction (BVI) noise is a main noise source from a rotorcraft and has been a barrier to wide acceptance for applications of rotorcrafts. In order to predict the noise accurately, it is required to consider characteristics of rotor blades having high aspect ratio as well as flow-unsteadiness around Size: KB.

ment of blade vortex interaction noise sensitivity to changes in the vortex field and the rotor operating conditions.

Theoretical Approach - The present analysis transforms the incident vor. It is shown for the scaled rotor that during descent, impulsive blade- vortex interaction (BVI) noise is the dominant con- tributor to the noise.

In level flight and mild climb, broadband blade-turbulent wake interaction (BWI) noise is dominant due to the avoidance of BVI activ- Size: 4MB. dominated by tail rotor noise sources, the primary cause of the noisiest flight conditions is main rotor Blade-Vortex Interaction (BVI).

(a) Top view. (b) Shallow descent. (c) Steep descent. (d) Steeper descent. Fig. 1: The wake geometry governing BVI noise. BVI occurs when the blades near the rear of the rotor disk pass close by the tip vorticesFile Size: 6MB. BWI noise is a broadband noise source due to the interaction of the rotor blades with the turbulent portion of the wakes of previous blades, particularly about tip vortices [17].

Martin RM, Marcolini MA, Splettstoesser WR, Schultz KJ () Wake geometry effects on rotor blade/vortex interaction noise directivity. NASA. Helicopter blade-vortex interaction (BVI) noise is known as a critical source of noise annoyance from helicopters.

A key feature of the noise is that the trace velocities of the sources generated by the BVI process are supersonic, and thus have high radiation by: 3. Get this from a library. Wake geometry effects on rotor blade-vortex interaction noise directivity. [R M Martin; United States. National Aeronautics and Space Administration.

Scientific and Technical Information Division.;]. broadband noise sources are namely due to blade wake interactions (BWI noise), which is the interaction between a blade and the turbulent wakes of preceding blades, and the interaction between the airfoil blade and the turbulence produced in its own boundary layer and near wake (self noise).

Both BVI and BWI noise sources result from the blade. Analytical Prediction of the Pylon-Wake Effect on the Tonal Noise radiated by the Front-Rotor of CROR Propulsion Systems.

18 June A 3D analytical approach for Open rotor Blade Vortex Interaction(BVI) tonal noise. Broadband Noise Prediction from Rotor-Wake Interaction in Contra-Rotating Propfans.

crosswinds on main rotor harmonic noise radiation are assessed using a model of the Bell helicopter. Crosswinds are found to have a significant effect on Blade-Vortex Interaction (BVI) noise radiation when the helicopter is trimmed with File Size: KB.

Stewart Glegg, William Devenport, in Aeroacoustics of Low Mach Number Flows, Blade vortex interactions in compressible flow. Blade vortex interaction is an important source of sound in situations where a blade tip vortex on a rotor washes over a structure or is re-ingested into the rotor. An example is a helicopter executing a maneuver in.

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 N89. An acoustic source localization scheme applicable to noncompact moving sources is developed and applied to the blade-vortex interaction (BVI) noise data of a 40 % scale BO model rotor.

A generalized rotor wake code is employed to predict possible BVI locations on the rotor disk and is found useful in interpreting the acoustic localization.

Analytically predicted results of blade-vortex interaction (BVI) airloads, using the second- generation comprehensive helicopter analysis system (2GCHAS), are presented with the experimental results obtained from the higher-harmonic-control aeroacoustic rotor test (HART) program using a percent, Mach-scaled model of the hingeless BO main by: An electrically controlled rotor (ECR), also called a swashplateless rotor, replaces a swashplate with a trailing-edge flap system to implement primary rotor control.

To investigate the aerodynamic characteristics of an ECR in blade-vortex interaction (BVI) condition, an analysis model based on the viscous vortex particle method, ECR blade pitch equation, and the Cited by: 1.experience have tied the occurrence of BVI to interactions of the rotor blade with previously shed tip vortices.

This alone makes BVI noise more difficult than high-speed impulsive noise to quantify, for the radiated noise is at least a function of blade-vortex geometry and vortex strength, as well as of blade airfoil Size: 1MB.