Download or read book Flow Induced Oscillations in Rectangular Cavities written by Alan J. Bilanin and published by . This book was released on 1970 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Induced Pressure Oscillations in Shallow Cavities written by Hanno H. Heller and published by . This book was released on 1970 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents the results of an experimental wind-tunnel study of flow-induced pressure oscillations in shallow cavities (length-to-depth ratio from 4 to 7). A variable-depth rectangular cavity was exposed to tangential flow over the open surface in the Mach-number range from 0.8 to 3, with flow stagnation pressures varying from 2 to 15 psia. The cavity was tested in an empty stage and with one or two stores. Third-octave band and narrowband fluctuating-pressure spectra were obtained at various locations within the cavity and under the approaching boundary layer; these spectra yielded information on broadband and resonant response characteristics. Information on the longitudinal and lateral energy distribution, on recirculating-flow velocities, and on temperatures within the cavity was also obtained. This information was used to develop a scheme for predicting resonant frequencies and associated pressure-mode shapes, as well as discrete-frequency and broadband pressure amplitudes.
Download or read book Suppression of Flow induced Pressure Oscillations in Cavities written by M. E. Franke and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Flow induced Cavity Resonance written by Paul Zoccola (Jr., J.) and published by . This book was released on 2000 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Induced Resonance of Screen Covered Cavities written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-03 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study of screen-covered cavities exposed to airflow tangent to the screen is described. The term screen refers to a thin metal plate perforated with a repetitive pattern of round holes. The purpose was to find the detailed aerodynamic and acoustic mechanisms responsible for screen-covered cavity resonance and to find ways to control the pressure oscillations. Results indicate that strong cavity acoustic resonances are created by screen orifices that shed vortices which couple resonance by choosing hole spacings such that shed vortices do not arrive at a downstream orifice in synchronization with cavity pressure oscillations. The proper hole pattern is effective at all airspeeds. It was also discovered that a reduction of orifice size tended to weaken the screen/cavity interaction regardless of hole pattern, probably because of viscous flow losses at the orifices. The screened cavities that resonated did so at much higher frequencies than the equivalent open cavity. The classical large eddy phenomenon occurs at the relatively small scale of the orifices (the excitation is typically of high frequency). The wind tunnel study was made at airspeeds from 0 to 100m/sec. The 457-mm-long by 1.09-m-high rectangular cavities had length-to-depth ratios greater than one, which is indicative of shallow cavities. The cavity screens were perforated in straight rows and columns with hole diameters ranging from 1.59 to 6.35 mm and with porosities from 2.6 to 19.6 percent. Soderman, Paul T. Ames Research Center RTOP 505-61-11...
Download or read book Mechanics of Flow Induced Sound and Vibration V1 written by William K. Blake and published by Elsevier. This book was released on 2012-12-02 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanics of Flow-Induced Sound and Vibration: Volume 1 discusses a broad selection of flow sources that are widely encountered in many applications of subsonic flow engineering and provides combined physical and mathematical analyses of each of these sources. It classifies each of the leading sources of vibration and sound induced by various types of fluid motion and unifies the disciplines essential to describing each source. The book considers sources such as jet noise, flow-induced tones and self-excited vibration, dipole sound from rigid and flexible acoustically compact surfaces, random vibration of flow-excited plates and cylindrical shells, cavitation noise, acoustic transmission characteristics and sound radiation from bubbly liquids, splash noise, throttling and ventilation system noises, lifting surface flow noise and vibration, and tonal and broadband sounds from rotating machinery. It also integrates the fundamentals of the subject with the many practicalities of the design of quiet vibration-free machinery. This book caters to advanced students well-versed in applied mathematics, fluid mechanics, and vibrations, strength of materials, acoustics, and statistical methods.
Download or read book Engineering Model of Unsteady Flow in a Cavity written by R. C. Bauer and published by . This book was released on 1991 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: A mathematical model was assembled from fundamental fluid dynamic relations and turbulent single-stream mixing zone relations to predict spectra, i.e., the frequency and amplitude, of unsteady pressures acting in a rectangular cavity exposed to an external flow parallel to the cavity opening. Characteristics of the approaching boundary layer are expected as inputs, thereby allowing computation of spectra for cases of mass-injection upstream of the cavity. The equations were compiled as a code (CAP) that can be run in less than 15 sec on a personal computer. Maximum dynamic loads acting on the contents of the cavity can be estimated, in addition to the primary frequencies of oscillation.
Download or read book Flow Induced Vibrations written by Eduard Naudascher and published by Courier Corporation. This book was released on 2012-03-27 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite their variety, the vibration phenomena from many different engineering fields can be classified into a relatively few basic excitation mechanisms. The classification enables engineers to identify all possible sources of excitation in a given system and to assess potential dangers. This graduate-level text presents a synthesis of research results and practical experience from disparate fields in the form of engineering guidelines. It is particularly geared toward assessing the possible sources of excitation in a flow system, in identifying the actual danger spots, and in finding appropriate remedial measures or cures. Flow-induced vibrations are presented in terms of their basic elements: body oscillators, fluid oscillators, and sources of excitation. By stressing these basic elements, the authors provide a basis for the transfer of knowledge from one system to another, as well as from one engineering field to another. In this manner, well-known theories on cylinders in cross-flow or well-executed solutions from the field of wind engineering--to name just two examples--may be useful in other systems or fields on which information is scarce. The unified approach is broad enough to permit treatment of the major excitation mechanism, yet simple enough to be of practical use.
Download or read book Flow induced Vibrations an Engineering Guide written by Eduard Naudascher and published by Routledge. This book was released on 2017-11-13 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed for engineers, this work considers flow-induced vibrations. It covers topics such as body oscillators; fluid loading and response of body oscillators; fluid oscillators; vibrations due to extraneously-induced excitation; and vibrations due to instability-induced excitation.
Download or read book Mach 0 6 to 3 0 Flows Over Rectangular Cavities written by Louis G. Kaufman and published by . This book was released on 1983 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal weapons carriage in high performance aircraft is often adversely affected by the severe aeroacoustic environment produced with the weapons bay doors open. To obtain a better understanding of this fluid dynamic problem, basic static and oscillatory pressure data were obtained for Mach 0.6 to 3.0 flows over shallow rectangular cavities in a generic flat plate model. Cavity length to depth ratios were varied from approximately 5 to 10. Static pressure data characteristic of both open and closed cavity flows were obtained. An improved Rossiter method is presented that satisfactorily predicts the possible frequency modes within the cavity. Highest fluctuating pressure occurs on the aft bulkhead, peaking near Mach 1.5 for the conditions tested. Aeroacoustic levels are substantially reduced by installing suppression fences (spoilers) at subsonic and low supersonic conditions. Acoustic levels generally drop rapidly above Mach 1.5. (Author).
Download or read book Mechanics of Flow Induced Sound and Vibration Volume 1 written by William K. Blake and published by Academic Press. This book was released on 2017-06-13 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanics of Flow-Induced Sound and Vibration, Volume 1: General Concepts and Elementary Sources, 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 with 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 jet noise, flow tones, dipole sound from cylinders, and cavitation noise. Step-by-step derivations clearly identify any assumptions made throughout. Each chapter is illustrated with comparisons of leading formulas and measured data. Along with its companion, Mechanics of Flow-Induced Sound and Vibration, Volume 2: Complex Flow-Structure Interactions, the book covers everything an engineer needs to understand flow-induced sound and vibration. This book will be essential reading for postgraduate students, and for 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 Measurements of Fluctuating Pressure in a Rectangular Cavity in Transonic Flow at High Reynolds Numbers written by M. B. Tracy and published by . This book was released on 1992 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Suppression of Aerodynamically Induced Cavity Pressure Oscillations written by Leonard L. Shaw and published by . This book was released on 1979 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: A flight test program was performed to gain further insight into the phenomenon of flow-induced cavity pressure oscillations and to evaluate the effectiveness of suppression concepts in eliminating or reducing the pressure oscillations. The cavities tested were rectangular with approximate dimensions of 17 inches long, 8.5 inches deep, and 8.75 inches wide and were instrumented with microphones, static pressure ports, and a thermocouple. The flight speeds ranged from Mach number 0.6 to 1.3 at pressure altitudes of 3,000, 20,000, and 30,000 feet. The suppression devices included leading edge spoilers and deflectors and trailing edge ramps and deflectors. Several combinations of these were tested. The results indicate that the flow-induced pressure oscillations in a cavity of the dimensions tested and for the speed range tested can be significantly reduced with leading edge spoilers in conjunction with a trailing edge ramp. Reductions as large as 30 dB were achieved for the predominant model frequency for a one-third octave band. Other combinations of the suppression devices afforded some reduction, but the spoiler ramp combination proved most effective. (Author).
Download or read book NASA Technical Note written by and published by . This book was released on 1976 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cavity Unsteady Pressure Measurements at Subsonic and Transonic Speeds written by Maureen B. Tracy and published by . This book was released on 1997 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Shock and Vibration Bulletin written by and published by . This book was released on 1974-08 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scramjets written by Mostafa Barzegar Gerdroodbary and published by Butterworth-Heinemann. This book was released on 2020-07-21 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet engines are a type of jet engine and rely on the combustion of fuel and an oxidizer to produce thrust. While scramjets are conceptually simple, actual implementation is limited by extreme technical challenges. Hypersonic flight within the atmosphere generates immense drag, and temperatures found on the aircraft and within the engine can be much greater than that of the surrounding air. Maintaining combustion in the supersonic flow presents additional challenges, as the fuel must be injected, mixed, ignited, and burned within milliseconds. Fuel mixing, along with the configuration and positioning of the injectors and the boundary conditions, play a key role in combustion efficiency. Scramjets: Fuel Mixing and Injection Systems discusses how fuel mixing efficiency and the advantage of injection systems can enhance the performance of the scramjets. The book begins with the introduction of the supersonic combustion chamber and explains the main parameters on the mixing rate. The configuration of scramjets is then introduced with special emphasis on the main effective parameters on the mixing of fuel inside the scramjets. In addition, basic concepts and principles on the mixing rate and fuel distribution within scramjets are presented. Main effective parameters such as range of fuel concentration for the efficient combustion, pressure of fuel jet and various arrangement of jet injections are also explained. This book is for aeronautical and mechanical engineers as well as those working in supersonic combustion who need to know the effects of compressibility on combustion, of shocks on mixing and on chemical reactions, and vorticity on the flame anchoring. - Explains the main applicable approaches for enhancement of supersonic combustion engines and the new techniques of fuel injection - Shows how the interaction of main air stream with fuel injections can develop the mixing inside the scramjets - Presents results of numerical simulations and how they can be used for the development of the combustion engines
