Download or read book Noise Sources in Turbulent Shear Flows Fundamentals and Applications written by Roberto Camussi and published by Springer Science & Business Media. This book was released on 2013-02-11 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The articles in this volume present the state-of-the-art in noise prediction, modeling and measurement. The articles are partially based on class notes provided during the course `Noise sources in turbulent shear flows', given at CISM on April 2011. The first part contains general concepts of aero acoustics, including vortex sound theory and acoustic analogies, in the second part particular emphasis is put into arguments of interest for engineers and relevant for aircraft design: jet noise, airfoil broadband noise, boundary layer noise (including interior noise and its control) and the concept of noise sources, their theoretical modeling and identification in turbulent lows. All these arguments are treated extensively with the inclusion of many practical examples and references to engineering applications.

Download or read book Aeroacoustics of Low Mach Number Flows written by Stewart Glegg and published by Elsevier. This book was released on 2023-09-26 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aeroacoustics of Low Mach Number Flows: Fundamentals, Analysis and Measurement, Second Edition provides a detailed introduction to sound radiation from subsonic flow over moving surfaces. This phenomenon is the most widespread cause of flow noise in engineering systems, including fan noise, rotor noise, wind turbine noise, boundary layer noise, airframe noise and aircraft noise. This fully updated new edition includes additional problems, illustrations and summary materials to support readers. New content covers Rapid Distortion theory (RDT), boundary layer wall pressure fluctuations, and flow induced sound at surfaces. Themes addressing non-compressible flows have also been added, offering coverage of hydroacoustic as well as aeroacoustic applications. New support materials for this edition include course outlines, problem sets, sample MATLAB codes and experimental data to be found at www.aeroacoustics.net. - Addresses, in detail, sound from rotating blades, ducted fans, airframes, boundary layers, and more - Presents theory in such a way that it can be used in computational methods and calculating sound levels - Includes coverage of different experimental approaches to this subject

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 Proceedings of XXIV AIMETA Conference 2019 written by Antonio Carcaterra and published by Springer Nature. This book was released on 2020-03-31 with total page 2200 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the peer-reviewed papers presented at the XXIV Conference of the Italian Association of Theoretical and Applied Mechanics, held in Rome, Italy, on September 15-19, 2019 (AIMETA 2019). The conference topics encompass all aspects of general, fluid, solid and structural mechanics, as well as mechanics for machines and mechanical systems, including theoretical, computational and experimental techniques and technological applications. As such the book represents an invaluable, up-to-the-minute tool, providing an essential overview of the most recent advances in the field.

Download or read book Fundamentals of Aeroacoustics with Applications to Aeropropulsion Systems written by Xiaofeng Sun and published by Elsevier. This book was released on 2020-10-14 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Aeroacoustics with Applications to Aeropropulsion Systems from the Shanghai Jiao Tong University Press Aerospace series, is the go-to reference on the topic, providing a modern take on the fundamental theory and applications relating to prediction and control of all major noise sources in aeropropulsion systems. This important reference compiles the latest knowledge and research advances, considering both the physics of aerodynamic noise generation in aero-engines and related numerical prediction techniques. Additionally, it introduces new vortex sound interaction models, a transfer element method, and a combustion instability model developed by the authors. Focusing on propulsion systems from inlet to exit, including combustion noise, this new resource will aid graduate students, researchers, and R&D engineers in solving the aircraft noise problems that currently challenge the industry. Updates the knowledge-base on the sound source generated by aeropropulsion systems, from inlet to exit, including combustion noise Covers new aerodynamic noise control technology aimed at the low-noise design of next generation aero-engines, including topics such as aerodynamic noise and aero-engine noise control Includes new, cutting-edge models and methods developed by an author team led by the editor-in-chief of the Chinese Journal of Aeronautics and Astronautics Considers both the physics of aerodynamic noise generation in aero-engines and related numerical prediction techniques

Download or read book Some Remarks on the Theory of Noise Generation by Turbulent Shear flows written by Wiktor Eckhaus and published by . This book was released on 1960 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Encyclopedia of Microfluidics and Nanofluidics written by Dongqing Li and published by Springer Science & Business Media. This book was released on 2008-08-06 with total page 2242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering all aspects of transport phenomena on the nano- and micro-scale, this encyclopedia features over 750 entries in three alphabetically-arranged volumes including the most up-to-date research, insights, and applied techniques across all areas. Coverage includes electrical double-layers, optofluidics, DNC lab-on-a-chip, nanosensors, and more.

Download or read book Handbook of Noise and Vibration Control written by Malcolm J. Crocker and published by John Wiley & Sons. This book was released on 2007-10-05 with total page 1594 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two of the most acclaimed reference works in the area of acoustics in recent years have been our Encyclopedia of Acoustics, 4 Volume set and the Handbook of Acoustics spin-off. These works, edited by Malcolm Crocker, positioned Wiley as a major player in the acoustics reference market. With our recently published revision of Beranek & Ver's Noise and Vibration Control Engineering, Wiley is a highly respected name in the acoustics business. Crocker's new handbook covers an area of great importance to engineers and designers. Noise and vibration control is one largest areas of application of the acoustics topics covered in the successful encyclopedia and handbook. It is also an area that has been under-published in recent years. Crocker has positioned this reference to cover the gamut of topics while focusing more on the applications to industrial needs. In this way the book will become the best single source of need-to-know information for the professional markets.

Download or read book An Experimental Investigation of the Influence of Air Bubbles on the Acoustic Radiation Efficiency of Turbulent Shear Flow written by Roger E. A. Arndt and published by . This book was released on 1987 with total page 20 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 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acoustic Excitation A Promising New Means of Controlling Shear Layers written by and published by . This book was released on 1984 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Jet Noise Source Localization and Identification written by Unnikrishnan Sasidharan Nair and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The exact mechanism by which turbulent fluctuations in jets are converted into acoustic energy remains unexplained. The current work aims to improve our understanding of this problem by localizing acoustic sources and identifying its causal dynamics. We use Large-Eddy Simulations of a Mach 1.3 turbulent cold jet for this purpose. The localization question is resolved by using a novel technique, termed Synchronous Large-Eddy Simulations (SLES), that tracks the non-linear evolution of small perturbations from any region (window) in a time-varying base flow. This provides superior insights into the generation of intermittency and directivity compared to traditional approaches that use linear stability analyses based on steady basic states or backward correlations between different regions of the flow. In SLES, two simulations are performed in a lock-step manner. At each step, native fluctuations from a desired spatial window in the first (or baseline simulation) are scaled to small values and then injected into the second (or twin simulation) to provide a forcing in the targeted region. At subsequent times, the difference between the two simulations provides a snapshot of the evolution of the perturbation field associated with the continuous forcing in the chosen spatial window. The perturbation field, which is equivalent to the solution of the forced Navier-Stokes equations linearized about the time-evolving base flow, is then statistically analyzed to identify its modulation by the turbulent region of the jet. Results are distilled by examining forcing at lipline and centerline locations in detail. The end of the potential core is found to be a sensitive zone where perturbations are amplified and lead to secondary sources. Perturbations within the shear layer on the other hand, are initially channeled toward the core and undergo higher amplification compared to those originating from the centerline, before propagating outward. Statistical analyses quantify intermittent events which have a major role in creating the nearfield sound signature and yield polar variation of the most significant frequency band. The flowfield is decomposed into its acoustic, hydrodynamic and thermal modes (which are referred to as the Fluid-Thermodynamic (FT) modes) using the Momentum Potential Theory to identify the acoustic sources and extract the propagated field of the jet. The hydrodynamic mode highlights the shear layer roll up and turbulent mixing, while the acoustic and thermal modes exhibit a wavepacket nature in the core. The acoustic wavepacket develops into the nearfield radiation pattern of the jet, with spatio-temporal amplifications in the core due to the presence of vorticity resulting in nearfield intermittent events. The acoustic and hydrodynamic modes closely follow the theoretical decay rates and the former possess the features of experimentally observed model sound spectra along the downstream and sideline polar angles. Inter-modal energy transfers in the non-linear flow are analyzed using the transport equation for the universal acoustic variable, Total Fluctuating Enthalpy (TFE). Production terms of TFE identify intruding vortices in the potential core as the principal physical mechanism by which intermittent acoustic sources are generated in the jet. The acoustic wavepacket and its nearfield fluctuations play a central role in transporting TFE utward from the core, resulting in the near and farfield sound signature of the jet. The present work provides unique insights into time-accurate linear response of a turbulent jet, and quantifies the relative prominence of various core locations in generating the nearfield acoustic signature. The evolution of the linear perturbation field highlights the modulation of random turbulent fluctuations into spatio-temporally persistent intermittent events. While the intermediate frequencies in the jet propagate in the upstream direction, the highest and lowest frequency-bands prevail in the sideline and downstream directions respectively. The FT mode decomposition elucidates the energy transfer mechanisms in the jet. It provides a phenomenological model to explain the amplification of the acoustic mode, leading to intermittent sound events in the nearfield as well as generation of acoustic sources. The FT modes also quantify the net energy flux scattered and transmitted out of the jet, delineating the stochastic turbulence from a relatively orderly acoustic transport.

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 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:

Download or read book Noise Identification in a Hot Transonic Jet Using Low dimensional Methods written by André M. Hall and published by . This book was released on 2008 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this effort has been to identify the dominant source of the radiated aero-acoustic noise produced by high-speed, heated jets and develop control strategies to reduce it. To that end, two acoustically matched Mach 0.6 jets, at temperature ratio Tr=O.93 (cold) and Tr=1.7 (hot) are examined. The use of non-intrusive Particle Image Velocimetry (PIV) to sample the flow, allowed a true measure of the velocity field to be realized without fear of corrupting the radiated noise field intrinsic to each jet. The low-order modal dominance of each was determined using Proper Orthogonal Decomposition (POD), highlighting the low-dimensional nature of this highly turbulent flow field.

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 Turbulent Noise Sources for Speech written by Thomas J. Hixon and published by . This book was released on 1975 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: