Download or read book The Prediction of Broadband Shock associated Noise Using Reynolds averaged Navier Stokes Solutions written by Steven Arthur Eric Miller and published by . This book was released on 2009 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Broadband shock-associated noise is a component of jet noise generated by supersonic jets operating off-design. It is characterized by multiple broadband peaks and dominates the total noise at large angles to the jet downstream axis. A new model is introduced for the prediction of broadband shock-associated noise that uses the solution of the Reynolds averaged Navier-Stokes equations. The noise model is an acoustic analogy based on the linearized Euler equations. The equivalent source terms depend on the product of the fluctuations associated with the shock cell structure and the turbulent velocity fluctuations in the jet shear layer. The former are deterministic and are obtained from the Reynolds averaged Navier-Stokes solution. A statistical model is introduced to describe the properties of the turbulence. Only the geometry and operating conditions of the nozzle need to be known to make noise predictions. Unlike other models, the developed broadband shock-associated noise model is a true prediction scheme and not calibrated for a finite range of operating conditions. The broadband shock-associated noise model developed represents the only prediction method in existence that has no restrictions on nozzle geometry or jet operating conditions. This overcomes the limitations and empiricism present in previous broadband shock-associated noise models. Extensive validation of the Reynolds averaged Navier-Stokes solution is performed using experimental data. Validation efforts of the Reynolds averaged Navier-Stokes solutions include comparisons of Pitot and static probe measurements and schlieren visualization. These validations show both the strengths and deficiencies for modeling strategies of supersonic jets operating off-design using Reynolds averaged Navier-Stokes equations and associated turbulence closure schemes. Predictions for various nozzle and operating conditions are compared with experimental noise measurements of the associated jets to validate the broadband shock-associated noise model. The operating conditions include under-expanded and over-expanded jets with and without heating.
Download or read book Prediction of Broadband Shock associated Noise in Static and Flight Conditions written by Cyprien Henry and published by . This book was released on 2012 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work aims at developing a statistical prediction method for BroadBand Shock-Associated Noise (BBSAN), following recent work from NASA and Boeing. The approach is similar to studies performed for mixing noise models.First, a methodology has been developed to compute the mean turbulent _ow _eld using the Reynolds Averaged Navier-Stokes (RANS) equations. These equations are solved with elsA, a solver developed by ONERA. Most calculations have been performed on academic configurations. An extensive test campaign has been conducted on these configurations at Ecole Centrale de Lyon (ECL), so that calculations have been thoroughly compared to measurements. Mainly, two operating conditions have been tested. The first one is a jet at Mj = 1:15. This condition is typical of a civil engine in cruise. The second operating condition is a jet at Mj = 1:35, which rather concerns military engines.An acoustic model has been developed. It uses the RANS calculation as an input to compute Power Spectrum Densities (PSDs). The intermediate version of the model does not account for refraction effects: acoustic sources are propagated to the far-field using a free field Green's function. As will be seen, this gives good results on simple configurations.The model has been extended to account for refraction effects. This is achieved by computing a Green's function tailored to the problem. A ray tracing method coupled to an adjoint approach has been used to evaluate the Green's function. The computation of the Green's function has been validated for simple cases. The Green's function calculation has been coupled to the acoustic model. PSDs including refraction effects on dual-streamjets are presented.
Download or read book Computation of Supersonic Jet Noise Under Imperfectly Expanded Conditions written by Chan M. Kim and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Tech Briefs written by and published by . This book was released on 2016-03 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Survey of the Broadband Shock Associated Noise Prediction Methods written by Chan M. Kim and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1992 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP written by and published by . This book was released on 1991 with total page 384 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 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 90 3910 to 90 3935 written by and published by . This book was released on 1990 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2004 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Aeronautical Engineering written by and published by . This book was released on 1993 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)
Download or read book Engineering Turbulence Modelling and Experiments 4 written by D. Laurence and published by Elsevier. This book was released on 1999-04-14 with total page 975 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings contain the papers presented at the 4th International Symposium on Engineering Turbulence Modelling and Measurements held at Ajaccio, Corsica, France from 24-26 May 1999. It follows three previous conferences on the topic of engineering turbulence modelling and measurements. The purpose of this series of symposia is to provide a forum for presenting and discussing new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. Turbulence is still one of the key issues in tackling engineering flow problems. As powerful computers and accurate numerical methods are now available for solving the flow equations, and since engineering applications nearly always involve turbulence effects, the reliability of CFD analysis depends more and more on the performance of the turbulence models. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation.
Download or read book AIAA Aerospace Sciences Meeting and Exhibit 42nd written by and published by . This book was released on 2004 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Aeroacoustics written by Jay C. Hardin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational aeroacoustics is rapidly emerging as an essential element in the study of aerodynamic sound. As with all emerging technologies, it is paramount that we assess the various opportuni ties and establish achievable goals for this new technology. Essential to this process is the identification and prioritization of fundamental aeroacoustics problems which are amenable to direct numerical siIn ulation. Questions, ranging from the role numerical methods play in the classical theoretical approaches to aeroacoustics, to the correct specification of well-posed numerical problems, need to be answered. These issues provided the impetus for the Workshop on Computa tional Aeroacoustics sponsored by ICASE and the Acoustics Division of NASA LaRC on April 6-9, 1992. The participants of the Work shop were leading aeroacousticians, computational fluid dynamicists and applied mathematicians. The Workshop started with the open ing remarks by M. Y. Hussaini and the welcome address by Kristin Hessenius who introduced the keynote speaker, Sir James Lighthill. The keynote address set the stage for the Workshop. It was both an authoritative and up-to-date discussion of the state-of-the-art in aeroacoustics. The presentations at the Workshop were divided into five sessions - i) Classical Theoretical Approaches (William Zorumski, Chairman), ii) Mathematical Aspects of Acoustics (Rodolfo Rosales, Chairman), iii) Validation Methodology (Allan Pierce, Chairman), iv) Direct Numerical Simulation (Michael Myers, Chairman), and v) Unsteady Compressible Flow Computa tional Methods (Douglas Dwoyer, Chairman).
Download or read book Aeroacoustics of Low Mach Number Flows written by Stewart Glegg and published by Academic Press. This book was released on 2017-02-15 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aeroacoustics of Low Mach Number Flows: Fundamentals, Analysis, and Measurement provides a comprehensive treatment of sound radiation from subsonic flow over moving surfaces, which is the most widespread cause of flow noise in engineering systems. This includes fan noise, rotor noise, wind turbine noise, boundary layer noise, and aircraft noise. Beginning with fluid dynamics, the fundamental equations of aeroacoustics are derived and the key methods of solution are explained, focusing both on the necessary mathematics and physics. Fundamentals of turbulence and turbulent flows, experimental methods and numerous applications are also covered. The book is an ideal source of information on aeroacoustics for researchers and graduate students in engineering, physics, or applied math, as well as for engineers working in this field. Supplementary material for this book is provided by the authors on the website www.aeroacoustics.net. The website provides educational content designed to help students and researchers in understanding some of the principles and applications of aeroacoustics, and includes example problems, data, sample codes, course plans and errata. The website is continuously being reviewed and added to. Explains the key theoretical tools of aeroacoustics, from Lighthill’s analogy to the Ffowcs Williams and Hawkings equation Provides detailed coverage of sound from lifting surfaces, boundary layers, rotating blades, ducted fans and more Presents the fundamentals of sound measurement and aeroacoustic wind tunnel testing
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
