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Tilt Rotor Hover Aeroacoustics
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Author :David Rudolf Polak Publisher :Ann Arbor, Mich. : University Microfilms International ISBN 13 : Total Pages :634 pages Book Rating :4.E/5 ( download)
Book Synopsis Experimental and Computational Investigation of Tilt Rotor Hover Aeroacoustics by : David Rudolf Polak
Download or read book Experimental and Computational Investigation of Tilt Rotor Hover Aeroacoustics written by David Rudolf Polak and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 1996 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781723460241 Total Pages :200 pages Book Rating :4.4/5 (62 download)
Book Synopsis Tilt Rotor Hover Aeroacoustics by : National Aeronautics and Space Administration (NASA)
Download or read book Tilt Rotor Hover Aeroacoustics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The methodology, results, and conclusions of a study of tilt rotor hover aeroacoustics and aerodynamics are presented. Flow visualization and hot wire velocity measurement were performed on a 1/12-scale model of the XV-15 Tilt Rotor Aircraft in hover. The wing and fuselage below the rotor cause a complex recirculating flow. Results indicate the physical dimensions and details of the flow including the relative unsteadiness and turbulence characteristics of the flow. Discrete frequency harmonic thickness and the loading noise mechanism were predicted using WOPWOP for the standard metal blades and the Advanced Technology Blades. The recirculating flow created by the wing below the rotor is a primary sound mechanism for a hovering tilt rotor. The effects of dynamic blade response should be included for fountain flow conditions which produce impulsive blade loading. Broadband noise mechanisms were studied using Amiet's method with azimuthally varying turbulence characteristics derived from the measurements. The recirculating fountain flow with high turbulence levels in the recirculating zone is the dominant source of broadband noise for a hovering rotor. It is shown that tilt rotor hover aeroacoustic noise mechanisms are now understood. Noise predictions can be made based on reasonably accurate aerodynamic models developed here. Coffen, Charles David Unspecified Center AEROACOUSTICS; AIRCRAFT NOISE; FLOW VISUALIZATION; HOVERING; NOISE PREDICTION (AIRCRAFT); ROTOR AERODYNAMICS; TILT ROTOR AIRCRAFT; XV-15 AIRCRAFT; AERODYNAMIC CHARACTERISTICS; AIRCRAFT MODELS; BROADBAND; DYNAMIC RESPONSE; FREQUENCIES; VELOCITY MEASUREMENT...
Book Synopsis Tilt Rotor Hover Aeroacoustics by : Charles David Coffen
Download or read book Tilt Rotor Hover Aeroacoustics written by Charles David Coffen and published by . This book was released on 1992 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tilt Rotor Hover Aeroacoustics written by and published by . This book was released on 1992 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722498092 Total Pages :40 pages Book Rating :4.4/5 (98 download)
Book Synopsis Prediction of XV-15 Tilt Rotor Discrete Frequency Aeroacoustic Noise with Wopwop by : National Aeronautics and Space Administration (NASA)
Download or read book Prediction of XV-15 Tilt Rotor Discrete Frequency Aeroacoustic Noise with Wopwop written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results, methodology, and conclusions of noise prediction calculations carried out to study several possible discrete frequency harmonic noise mechanisms of the XV-15 Tilt Rotor Aircraft in hover and helicopter mode forward flight are presented. The mechanisms studied were thickness and loading noise. In particular, the loading noise caused by flow separation and the fountain/ground plane effect were predicted with calculations made using WOPWOP, a noise prediction program developed by NASA Langley. The methodology was to model the geometry and aerodynamics of the XV-15 rotor blades in hover and steady level flight and then create corresponding FORTRAN subroutines which were used an input for WOPWOP. The models are described and the simplifying assumptions made in creating them are evaluated, and the results of the computations are presented. The computations lead to the following conclusions: The fountain/ground plane effect is an important source of aerodynamic noise for the XV-15 in hover. Unsteady flow separation from the airfoil passing through the fountain at high angles of attack significantly affects the predicted sound spectra and may be an important noise mechanism for the XV-15 in hover mode. The various models developed did not predict the sound spectra in helicopter forward flight. The experimental spectra indicate the presence of blade vortex interactions which were not modeled in these calculations. A need for further study and development of more accurate aerodynamic models, including unsteady stall in hover and blade vortex interactions in forward flight. Coffen, Charles D. and George, Albert R. Unspecified Center NAG2-554...
Book Synopsis The History of the XV-15 Tilt Rotor Research Aircraft by : Martin D. Maisel
Download or read book The History of the XV-15 Tilt Rotor Research Aircraft written by Martin D. Maisel and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis XV-15 Tiltrotor Aircraft: 1997 Acoustic Testing by : Bryan D. Edwards
Download or read book XV-15 Tiltrotor Aircraft: 1997 Acoustic Testing written by Bryan D. Edwards and published by . This book was released on 2003 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aeroacoustics of Flight Vehicles by : Harvey H. Hubbard
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Tilt Rotor Aeroacoustic Model Project by :
Download or read book Tilt Rotor Aeroacoustic Model Project written by and published by . This book was released on 1999 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new tiltrotor aeroacoustic research facility, the Tilt Rotor Aeroacoustic Model (TRAM), is being developed by NASA and the U.S. Army. The TRAM Project will enable new insights into the fundamental aeroacoustics of proprotors and tiltrotor aircraft, leading to improved acoustic prediction methodologies and noise reduction techniques. An overview of NASA's goals in understanding and reducing the technology barriers for civil tiltrotor aircraft is provided as well as a description of how TRAM will support these goals. TRAM is capable of being configured as an isolated rotor or as a complete full-span dual rotor aircraft model. The TRAM test stands and their modular, compatible sub-systems are described in detail. Sample results from an isolated rotor test recently completed at the Duits-Nederlandse Windtunnel are presented. The current status of the full-span model development is described.
Book Synopsis Tilt Rotor Aeroacoustic Model (TRAM): A New Rotorcraft Research Facility by :
Download or read book Tilt Rotor Aeroacoustic Model (TRAM): A New Rotorcraft Research Facility written by and published by . This book was released on 1998 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper introduces the Tilt Rotor Aeroacoustic Model "TRAM" project. The TRAM project is a key infrastructure investment for NASA and U.S. Army tiltrotor research. The TRAM project consists of the development and testing of two modular, hardware-compatible, test stands: an isolated rotor configuration and a full-span model "dual rotors with a complete airframe representation". These two test stands are inclusively called the Tilt Rotor Aeroacoustic Model "TRAM". The baseline proprotors and airframe of the TRAM test stands are nominally 1/4-scale representations of the V-22 Osprey aircraft. The research objectives of the project, the TRAM hardware design features and capabilities required to meet those objectives, and the status of the project are discussed in detail in this paper.
Book Synopsis Rotor/Wing Interactions in Hover by :
Download or read book Rotor/Wing Interactions in Hover written by and published by . This book was released on 2002 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Calculation of Tilt Rotor Aeroacoustic Model (TRAM DNW) Performance, Airloads, and Structural Loads by :
Download or read book Calculation of Tilt Rotor Aeroacoustic Model (TRAM DNW) Performance, Airloads, and Structural Loads written by and published by . This book was released on 2000 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comparisons of measured and calculated aeromechanics behavior of a tiltrotor model are presented, with an emphasis on performance and structural loads. The recent test of the Tilt Rotor Aeroacoustic Model (TRAM) with a single, 1/4-scale V-22 rotor in the German-Dutch Wind Tunnel (DNW) provides an extensive set of aeroacoustic, performance, and structural loads data. The calculations were performed using the rotorcraft comprehensive analysis CAMRAD II. The comparison of measurements and calculations includes helicopter mode operation (performance, airloads, and blade structural loads), hover performance, and airplane mode performance. The correlation establishes the level of predictive capability achievable with current technology; identifies the limitations of the current aerodynamic, wake, and structural models of tiltrotors; and leads to recommendations for research to extend tiltrotor aeromechanics analysis capability.
Book Synopsis Hover and Forward Flight Acoustics and Performance of a Small-scale Helicopter Rotor System by :
Download or read book Hover and Forward Flight Acoustics and Performance of a Small-scale Helicopter Rotor System written by and published by . This book was released on 1985 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A 2.1-m diam., 1/6-scale model helicopter main rotor was tested in hover in the test section of the NASA Ames 40- by 80-foot Wind Tunnel. Subsequently, it was tested in forward flight in the Ames 7- by 10-foot Wind Tunnel. The primary objective of the tests was to obtain performance and noise data on a small-scale rotor at various thrust coefficients, tip Mach numbers, and, in the latter case, various advance ratios, for comparison with similar existing data on full-scale helicopter rotors. This comparison yielded a preliminary evaluation of the scaling of helicopter rotor performance and acoustic radiation in hover and in forward flight. Correlation between model-scale and full-scale performance and acoustics was quite good in hover. In forward flight, however, there were significant differences in both performance and acoustic characteristics. A secondary objective was to contribute to a data base that will permit the estimation of facility effects on acoustic testing.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Book Synopsis Rotorcraft Aeromechanics by : Wayne Johnson
Download or read book Rotorcraft Aeromechanics written by Wayne Johnson and published by Cambridge University Press. This book was released on 2013-04-29 with total page 949 pages. Available in PDF, EPUB and Kindle. Book excerpt: A rotorcraft is a class of aircraft that uses large-diameter rotating wings to accomplish efficient vertical take-off and landing. The class encompasses helicopters of numerous configurations (single main rotor and tail rotor, tandem rotors, coaxial rotors), tilting proprotor aircraft, compound helicopters, and many other innovative configuration concepts. Aeromechanics covers much of what the rotorcraft engineer needs: performance, loads, vibration, stability, flight dynamics, and noise. These topics include many of the key performance attributes and the often-encountered problems in rotorcraft designs. This comprehensive book presents, in depth, what engineers need to know about modelling rotorcraft aeromechanics. The focus is on analysis, and calculated results are presented to illustrate analysis characteristics and rotor behaviour. The first third of the book is an introduction to rotorcraft aerodynamics, blade motion, and performance. The remainder of the book covers advanced topics in rotary wing aerodynamics and dynamics.
Book Synopsis Monthly Catalog of United States Government Publications by :
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Monthly Catalogue, United States Public Documents by :
Download or read book Monthly Catalogue, United States Public Documents written by and published by . This book was released on 1993 with total page 1790 pages. Available in PDF, EPUB and Kindle. Book excerpt:
