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Wednesday, May 13, 2020 | History

3 edition of Reduction of Blade-Vortex Interaction (BVI) noise through X-force control found in the catalog.

Reduction of Blade-Vortex Interaction (BVI) noise through X-force control

Reduction of Blade-Vortex Interaction (BVI) noise through X-force control

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  • 24 Currently reading

Published by National Aeronautics and Space Administration, Ames Research Center, National Technical Information Service, distributor in Moffett Field, Calif, [Springfield, Va .
Written in English

    Subjects:
  • Aeroacoustics.,
  • Aircraft landing.,
  • Blade slap noise.,
  • Blade-vortex interaction.,
  • Flight control.,
  • Flight paths.,
  • Helicopters.,
  • Inlet flow.,
  • Longitudinal stability.,
  • Noise prediction (Aircraft),
  • Noise reduction.

  • Edition Notes

    StatementFredric H. Schmitz.
    SeriesNASA technical memorandum -- 110371.
    ContributionsAmes Research Center.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15424058M

    For each member, a steady-state Reynolds-averaged Navier–Stokes (RANS) simulation is performed, which is coupled with an analytical noise prediction method in order to evaluate the noise reduction due to the serrations. The results confirm that tonal interaction noise can Cited by: 7. Oct 07,  · A rotor blade system with reduced blade-vortex interaction noise includes a plurality of tube members embedded in proximity to a tip of each rotor blade. The inlets of the tube members are arrayed at the leading edge of the blade slightly above the chord plane, while the outlets are arrayed at the blade tip face. A rotor blade system with reduced blade-vortex interaction noise includes a plurality of tube members embedded in proximity to a tip of each rotor blade. The inlets of the tube members are arrayed at the leading edge of the blade slightly above the chord plane, while the outlets are arrayed at the blade tip face. Such a design rapidly diffuses the vorticity contained within the concentrated Cited by: Concepts for reduction of blade-vortex interaction noise. J. HARDIN and.

    noise has been identified as blade vortex interaction (BVI), i.e., the interaction of the blade with the vortices shed by the preceding blade(s) [5], [12], [14]. Owing to the limitations of design in prediction and control of noise, the need to meet stricter restrictions on noise in the future, and in the interest. The results of this feasibility study suggest that active blade twist technology is a viable means to reduce blade- vortex interaction (BVI) noise in rotorcraft systems. A linearized unsteady aerodynamics analysis was formulated and successfully validated with computation fluid dynamics mkstores-eg.com by: 1. Jan 07,  · Blade Vortex interaction with Life Leech Mechanics Hello everyone, when I was leveling my first character in this league I was playing with all the new skill gems I could get my hands on. At one point I had blasphemy and warlord's mark running. American Institute of Aeronautics and Astronautics Sunrise Valley Drive, Suite Reston, VA

    A powerful experimental system comprises of a high resolution measuring equipment for the recording and a fast preprocessing capability. To capture rotor data these were decisive elements for the analysis of the blade vortex interaction (BVI) mkstores-eg.com: D. Schimke, Uwe T. P. Arnold, W. Geißler, R. Kube, W. R. Splettstösser. Helicopter blade-vortex interaction noise with comparisons to CFD calculations [microform] / Megan S. McCluer National Aeronautics and Space Administration ; National Technical Information Service, distributor [Washington, D.C.: Springfield, Va Australian/Harvard Citation. McCluer, Megan S. & . May 21,  · Vortex dynamics during parallel blade-vortex interactions (BVIs) were investigated in a subsonic wind tunnel using particle image velocimetry (PIV). Vortices were generated by applying a rapid pitch-up motion to an airfoil through a pneumatic system, and the subsequent interactions with a downstream, unloaded target airfoil were studied. The blade-vortex interactions may be classified into Cited by: DR. BARNES W. MCCORMICK Dr. McCormick was born in Waycross, Georgia, in He is married and has one daughter. Dr. McCormick received his B.S. degree in , his M.S. in , and his Ph.D. in , all from the Department of Aeronautical Engineering at The Pennsylvania State University.


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Reduction of Blade-Vortex Interaction (BVI) noise through X-force control Download PDF EPUB FB2

Helicopter noise reduction is a topic of research into designing helicopters which can Reduction of Blade-Vortex Interaction book 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. A blade vortex interaction (BVI) is Reduction of Blade-Vortex Interaction book 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 descending.

Additional Physical Format: Reduction of blade-vortex interaction noise using higher harmonic pitch control. 17 p. (OCoLC) Material Type: Document, Government publication, National government publication, Internet resource.

The HHC technique has proved the substantial blade–vortex interaction noise reduction, up to 6 dB, while vibration and low-frequency noise have been increased. Tests with IBC techniques have shown the simultaneous reduction of rotor noise and vibratory loads with 2/rev pitch control mkstores-eg.com by: Abstract Several ideas for the reduction of transonic blade-vortex interaction (BVI) noise are proposed and tested.

Noise due to transonic BVI is analyzed using a finite difference Reduction of Blade-Vortex Interaction book the numerically calculated 2D near-field aerodynamic results are extended to 3D linear acoustic far field using the Kirchhoff method.

Get this from a library. Reduction of Blade-Vortex Interaction (BVI) noise through X-force control. [Fredric H Schmitz; Ames Research Center.]. Reduction of helicopter blade-vortex interaction noise Substituting the conventional pitch links, these actuators make it possible to control each blade individually, while the implementation of the actuators below the swashplate affects all blades simultaneously, and due to the swashplate kinematics this concept is, in addition, limited to Cited by: REDUCTION OF BLADE-VORTEX INTERACTION NOISE IN ROTORCRAFT A Dissertation in Aerospace Engineering by Brendon D.

Malovrh Brendon D. Malovrh Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy December This paper deals with an efficient computational process for the synthesis of a low-frequency controller aimed at alleviating helicopter rotor blade–vortex interaction noise.

Helicopter Model Rotor-Blade Vortex Interaction Impulsive Noise: Scalability and Parametric Variations [W. Splettstoesser] on mkstores-eg.com *FREE* shipping on qualifying offers. Significant reduction of helicopter blade-vortex interaction (BVI) noise is currently one of the most advanced research topics in the helicopter industry.

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. Hardin J, Lamkin S () Concepts for reduction of blade–vortex interaction noise. J Aircr – CrossRef Google Scholar. Hassan A, Charles B, Tadghighi H, Sankar L () Blade-mounted trailing edge flap control for BVI noise reduction.

NASA CR Google mkstores-eg.com by: 6. Helicopter Tail Rotor Orthogonal Blade Vortex Interaction The pure orthogonal blade vortex interaction (OBVI) is, therefore, an important and new tail rotor, rotating top blade aft and with new aerofoils, a reduction in the acoustic signature [30] was observed.

It has also been possible to identify the. 2 analysis of the parallel blade vortex interaction with leading edge blowing flow control using the proper orthogonal decomposition 29 introduction 31 the proper orthogonal decomposition 32 nomenclature 34 reduction in rms level of airfoil vibration as a function of c.

Unfortunately, this book can't be printed from the OpenBook. If you need to print pages from this book, we recommend downloading it as a PDF.

Visit mkstores-eg.com to get more information about this book, to buy it in print, or to download it as a free PDF. Sep 15,  · HELICOPTER VIBRATION REDUCTION TECHNIQUES A SEMINAR REPORT Presented By: Haftamu Abraha Feb.

HELICOPTER VIBRATION REDUCTION TECHNIQUES A SEMINAR REPORT Presented By: Haftamu Abraha Feb. This condition is usually referred to as Blade Vortex Interaction (BVI) 11 Figure Blade Vortex Interaction (BVI) schematic In moderate. is now intrinsically unsteady because the speed of the interaction point is infinite.

The blade vortex interaction may then be classified by the two limiting conditions defined by 8 = ~/2 and 8 = T. The 8 = n/2 condition may be called a low speed interaction (LSI) since this is a steady problem even in the original coordinate system. Blade-vortex interaction noise is caused when a rotor blade passes close to the shed tip vortices of a previous blade.

This causes a rapid change in the loading of the blade and generates a highly directional impulsive loading noise.

BVI noise can occur on either the advancing or retreating side of the rotor blade. BLADE VORTEX INTERACTION RESEARCH IN THE By FOOT TUNNEL Objectives. Experimentally simulate the aerodynamics and acoustics of parallel (2-D), unsteady helicopter rotor blade-vortex interactions, in a manner closely matching the simplified computational models frequently used for numerical simulations.

mferential elocity of the pdf responsible for blade-vortex interaction noise was measured using a rotating hot-wire rake synchronously meshed with a model helicopter rotor at the blade passage frequency.

Simultaneous far-field acoustic data and blade .Blade - Vortex Interactions in High Pressure Steam Turbines by Venkata Siva Prasad Chaluvadi vortices in high-pressure axial turbines and their interaction with the downstream blade rows was performed.

The results indicate large variations in the .blade with the blade tip vortex is called Ebook Interaction (BVI) noise.

This is the recognizable “flapping” noise of a helicopter. BVI noise is most noticeable when the helicopter descends gently to land. The blade tip vortex moves downward during normal flight. .