Download or read book Basic Mechanisms of Noise Generation by Helicopters V stol Aircraft and Ground Effect Machines written by M. V. Lowson and published by . This book was released on 1965 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic mechanisms of noise generation due to mass introduction, applied force and applied stress are discussed with reference to their implications for helicopters, V/STOL aircraft, and Ground Effect Machines. The significance of the dimensional dependence of monopole, dipole and quadrupole fields is shown. The results of a new theory giving the effects of system accelerations on noise are presented. This theory will often have application to noise problems for these machines because of the centrifugal accelerations associated with many of the noise generating components. System accelerations give rise to higher order poles in the sound field which become particularly important at high speeds. An expression for the sound field produced by fluctuating lift and drag forces in a rotating and convected system is given. As a further example of the application of the general theory the sound field radiated by a hovering helicopter is analyzed. It is shown how a previously unrecognized source of sound arises from the outward components of force induced by the effects of blade coning angle and lag. The source of sound has its maximum in the plane of the rotor disc. The importance of including the proper momentum terms in calculations of noise radiated by moving mass sources is demonstrated. (Author).
Download or read book Aircraft Noise and Sonic Boom written by Louise K. Annus and published by . This book was released on 1966 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter and V STOL Noise Generation and Suppression written by National Academy of Engineering. AERONAUTICS AND SPACE ENGINEERING BOARD. and published by . This book was released on 1968 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent discussions between scientists of the United States Army Research Office, Durham, North Carolina, and members and staff of the National Academy of Sciences and National Academy of Engineering have identified an urgent need for renewed effort toward suppression of helicopter and V/STOL noise in military operations. Use of the term VTOL is intended to apply to all aircraft capable of vertical flight, of which the helicopter is the best known example. Major recommendations were: (1) Criteria should be established for determining the benefits and costs of noise reduction, on a quantitative basis in both military and commercial operations. (2) Factors determining aural detectability should be established for acoustic signatures of type generated by VTOL aircraft. Annoyance factors should also be established. (3) Mechanisms of noise generation by rotors and propellers should be established by a basic research program including analytical studies and experimental investigations. (4) Standards should be established for measurement of noise levels and data reduction which could be applied on a consistent basis by all investigators using commercially available equipment.
Download or read book Helicopter Theory written by Wayne Johnson and published by Courier Corporation. This book was released on 2012-03-07 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monumental engineering text covers vertical flight, forward flight, performance, mathematics of rotating systems, rotary wing dynamics and aerodynamics, aeroelasticity, stability and control, stall, noise, and more. 189 illustrations. 1980 edition.
Download or read book Mechanics of Flow Induced Sound and Vibration Volume 2 written by William K. Blake and published by Academic Press. This book was released on 2017-08-14 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanics of Flow-Induced Sound and Vibration, Volume 2: Complex Flow-Structure Interactions, Second Edition, enables readers to fully understand flow-induced vibration and sound, unifying the disciplines of fluid dynamics, structural dynamics, vibration, acoustics, and statistics in order to classify and examine each of the leading sources of vibration and sound induced by various types of fluid motion. Starting from classical theories of aeroacoustics and hydroacoustics, a formalism of integral solutions valid for sources near boundaries is developed and then broadened to address different source types, including hydrodynamically induced cavitation and bubble noise, turbulent wall-pressure fluctuations, pipe and duct systems, lifting surface flow noise and vibration, and noise from rotating machinery. Each chapter is illustrated with comparisons of leading formulas and measured data. Combined with its companion book, Mechanics of Flow-Induced Sound and Vibration, Volume 1: General Concepts and Elementary Sources, the book covers everything an engineer needs to understand flow-induced sound and vibration. This book will be a vital source of information for postgraduate students, engineers and researchers with an interest in aerospace, ships and submarines, offshore structures, construction, and ventilation. Presents every important topic in flow-induced sound and vibration Covers all aspects of the topics addressed, from fundamental theory, to the analytical formulas used in practice Provides the building blocks of computer modeling for flow-induced sound and vibration
Download or read book Mechanics of Flow Induced Sound and Vibration V2 written by William K. Blake and published by Elsevier. This book was released on 2012-12-02 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanics of Flow-Induced Sound and Vibration V2
Download or read book U S Government Research Development Reports written by and published by . This book was released on 1965-12 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research and Development Reports written by and published by . This book was released on 1965 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book DTNSRDC written by David W. Taylor Naval Ship Research and Development Center and published by . This book was released on 1984 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government wide Index to Federal Research Development Reports written by and published by . This book was released on 1966 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Aerodynamics of V STOL Aircraft written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development and published by . This book was released on 1968 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliographic List Library Branch Administrative Services Division Office of Management Services written by and published by . This book was released on 1962 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hovering Craft Hydrofoil written by and published by . This book was released on 1971 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transportation Noise Bulletin written by and published by . This book was released on 1972 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1973 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
