Coherent Large-scale Structures in High Reynolds Number Supersonic Jets

Coherent Large-scale Structures in High Reynolds Number Supersonic Jets PDF Author: J. Lepicovsky
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 112

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Book Description
The flow structure of a 50.8 mm (2 in) diameter jet operated at a full expanded Mach number of 1.37, with Reynolds numbers in the range 1.7 to 2.35 million, was examined for the first 20 jet diameters. To facilitate the study of the large scale structure, and determine any coherence, a discrete tone acoustic excitation method was used. Phase locked flow visualization as well as laser velocimeter quantitative measurements were made. The main conclusions derived from this study are: (1) large scale coherent like turbulence structures do exist in large Reynolds number supersonic jets, and they prevail even beyond the potential core; (2) the most preferential Strouhal number for these structures is in the vicinity of 0.4; and (3) quantitatively, the peak amplitudes of these structures are rather low, and are about 1% of the jet exit velocity. Finally, since a number of unique problems related to LV measurements in supersonic jets were encountered, a summary of these problems and lessons learned therefrom are also reported.

Coherent Large-scale Structures in High Reynolds Number Supersonic Jets

Coherent Large-scale Structures in High Reynolds Number Supersonic Jets PDF Author: J. Lepicovsky
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 112

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Book Description
The flow structure of a 50.8 mm (2 in) diameter jet operated at a full expanded Mach number of 1.37, with Reynolds numbers in the range 1.7 to 2.35 million, was examined for the first 20 jet diameters. To facilitate the study of the large scale structure, and determine any coherence, a discrete tone acoustic excitation method was used. Phase locked flow visualization as well as laser velocimeter quantitative measurements were made. The main conclusions derived from this study are: (1) large scale coherent like turbulence structures do exist in large Reynolds number supersonic jets, and they prevail even beyond the potential core; (2) the most preferential Strouhal number for these structures is in the vicinity of 0.4; and (3) quantitatively, the peak amplitudes of these structures are rather low, and are about 1% of the jet exit velocity. Finally, since a number of unique problems related to LV measurements in supersonic jets were encountered, a summary of these problems and lessons learned therefrom are also reported.

Aeroacoustics of Flight Vehicles

Aeroacoustics of Flight Vehicles PDF Author: Harvey H. Hubbard
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 620

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NASA Reference Publication

NASA Reference Publication PDF Author:
Publisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 628

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Theoretical and Applied Mechanics 1992

Theoretical and Applied Mechanics 1992 PDF Author: S.R. Bodner
Publisher: Elsevier
ISBN: 044460023X
Category : Science
Languages : en
Pages : 492

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Book Description
Contained in this volume are the full texts of the invited general and sectional lectures presented at this conference concerning mechanics and its development. The entire field of mechanics is covered, including analytical, solid and fluid mechanics and their applications. A brilliant survey of work in the fields of fluid and solid mechanics is also given. The papers are written by leading experts which is reflected in the quality and diversity of the lectures and posters presented, they will provide a valuable key to the latest and most important developments in the various sub-fields of mechanics.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 892

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Stability and Transition in Shear Flows

Stability and Transition in Shear Flows PDF Author: Peter J. Schmid
Publisher: Springer Science & Business Media
ISBN: 1461301858
Category : Science
Languages : en
Pages : 561

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Book Description
A detailed look at some of the more modern issues of hydrodynamic stability, including transient growth, eigenvalue spectra, secondary instability. It presents analytical results and numerical simulations, linear and selected nonlinear stability methods. By including classical results as well as recent developments in the field of hydrodynamic stability and transition, the book can be used as a textbook for an introductory, graduate-level course in stability theory or for a special-topics fluids course. It is equally of value as a reference for researchers in the field of hydrodynamic stability theory or with an interest in recent developments in fluid dynamics. Stability theory has seen a rapid development over the past decade, this book includes such new developments as direct numerical simulations of transition to turbulence and linear analysis based on the initial-value problem.

Annual Research Briefs ...

Annual Research Briefs ... PDF Author: Center for Turbulence Research (U.S.)
Publisher:
ISBN:
Category : Turbulence
Languages : en
Pages : 410

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Book Description


Future Propulsion Systems and Energy Sources in Sustainable Aviation

Future Propulsion Systems and Energy Sources in Sustainable Aviation PDF Author: Saeed Farokhi
Publisher: John Wiley & Sons
ISBN: 1119415055
Category : Technology & Engineering
Languages : en
Pages : 584

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Book Description
A comprehensive review of the science and engineering behind future propulsion systems and energy sources in sustainable aviation Future Propulsion Systems and Energy Sources in Sustainable Aviation is a comprehensive reference that offers a review of the science and engineering principles that underpin the concepts of propulsion systems and energy sources in sustainable air transportation. The author, a noted expert in the field, examines the impact of air transportation on the environment and reviews alternative jet fuels, hybrid-electric and nuclear propulsion and power. He also explores modern propulsion for transonic and supersonic-hypersonic aircraft and the impact of propulsion on aircraft design. Climate change is the main driver for the new technology development in sustainable air transportation. The book contains critical review of gas turbine propulsion and aircraft aerodynamics; followed by an insightful presentation of the aviation impact on environment. Future fuels and energy sources are introduced in a separate chapter. Promising technologies in propulsion and energy sources are identified leading to pathways to sustainable aviation. To facilitate the utility of the subject, the book is accompanied by a website that contains illustrations, and equation files. This important book: Contains a comprehensive reference to the science and engineering behind propulsion and power in sustainable air transportation Examines the impact of air transportation on the environment Covers alternative jet fuels and hybrid-electric propulsion and power Discusses modern propulsion for transonic, supersonic and hypersonic aircraft Examines the impact of propulsion system integration on aircraft design Written for engineers, graduate and senior undergraduate students in mechanical and aerospace engineering, Future Propulsion Systems and Energy Sources in Sustainable Aviation explores the future of aviation with a guide to sustainable air transportation that includes alternative jet fuels, hybrid-electric propulsion, all-electric and nuclear propulsion.

Compressibility, Turbulence and High Speed Flow

Compressibility, Turbulence and High Speed Flow PDF Author: Thomas B. Gatski
Publisher: Academic Press
ISBN: 012397318X
Category : Science
Languages : en
Pages : 343

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Book Description
Compressibility, Turbulence and High Speed Flow introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range, through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. The book provides the reader with the necessary background and current trends in the theoretical and experimental aspects of compressible turbulent flows and compressible turbulence. Detailed derivations of the pertinent equations describing the motion of such turbulent flows is provided and an extensive discussion of the various approaches used in predicting both free shear and wall bounded flows is presented. Experimental measurement techniques common to the compressible flow regime are introduced with particular emphasis on the unique challenges presented by high speed flows. Both experimental and numerical simulation work is supplied throughout to provide the reader with an overall perspective of current trends. - An introduction to current techniques in compressible turbulent flow analysis - An approach that enables engineers to identify and solve complex compressible flow challenges - Prediction methodologies, including the Reynolds-averaged Navier Stokes (RANS) method, scale filtered methods and direct numerical simulation (DNS) - Current strategies focusing on compressible flow control

Scientific and Technical Information Output of the Langley Research Center for Calendar Year 1985

Scientific and Technical Information Output of the Langley Research Center for Calendar Year 1985 PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 284

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Book Description