Download or read book Numerical Simulation of Free Shear Flows written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-23 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Implicit and explicit spatial differencing techniques with fourth order accuracy have been developed. The implicit technique is based on the Pade compact scheme. A Dispersion Relation Preserving concept has been incorporated into both of the numerical schemes. Two dimensional Euler computation of a spatially-developing free shear flow, with and without external excitation, has been performed to demonstrate the capability of numerical schemes developed. Results are in good agreement with theory and experimental observation regarding the growth rate of fluctuating velocity, the convective velocity, and the vortex-pairing process. Soh, W. Y. Unspecified Center NAS3-25266; RTOP 505-62-52...

Download or read book Numerical Simulation of Free Shear Flows written by United States. National Aeronautics and Space Administration and published by . This book was released on 1993 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Free Shear Flows Towards a Predictive Computational Aeroacoustics Capability written by and published by . This book was released on 1993 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Turbulent Flows and Noise Generation written by Christophe Brun and published by Springer Science & Business Media. This book was released on 2009-03-07 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large Eddy Simulation (LES) is a high-fidelity approach to the numerical simulation of turbulent flows. Recent developments have shown LES to be able to predict aerodynamic noise generation and propagation as well as the turbulent flow, by means of either a hybrid or a direct approach. This book is based on the results of two French/German research groups working on LES simulations in complex geometries and noise generation in turbulent flows. The results provide insights into modern prediction approaches for turbulent flows and noise generation mechanisms as well as their use for novel noise reduction concepts.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 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 1993 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1994 with total page 1828 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1994 with total page 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 1991 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unsteady Jet Flow Computation Towards Noise Prediction written by and published by . This book was released on 1994 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transition Turbulence and Noise written by Reda R. Mankbadi and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence takes place in most flow situations whethertheyoccur naturally or in technological systems. Therefore, considerable effort is being expended in an attempt to understand the phenomenon of turbulence. The recent discovery ofcoherent structure in turbulent shear flows and the modem developments in computer capabilities have revolutionized research work in turbulence. There is a strong evidence that the coherent structure in turbulent shear flows is reminiscent of nonlinear stability waves. As such, the interest in nonlinear stability waves has increased not only for the understandingofthe latterstages of the laminar-turbulent transition process, but also for understanding the coherent structures in turbulent flows. Also. the advances in computers have made direct numerical simulation possible at Low-Reynolds numbers and large-eddy simulation possible at high Reynolds numbers. This made first-principles prediction of turbulence-generated noise feasible. Therefore, this book aims at presenting a graduate-level introductory study of turbulence while accounting for such recent views of concern to researchers. This book is an outgrowth oflecture notes on the subject offered to graduate students in engineering. The book should be of interest to research engineers and graduatestudents in science and engineering. The theoretical basis presented is sufficient not only for studying the specialized literature on turbulence but also for theoretical investigations on the subject.

Download or read book Modeling of Turbulent Free Shear Flows written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The modeling of turbulent free shear flows is crucial to the simulation of many aerospace applications, yet often receives less attention than the modeling of wall boundary layers. Thus, while turbulence model development in general has proceeded very slowly in the past twenty years, progress for free shear flows has been even more so. This paper highlights some of the fundamental issues in modeling free shear flows for propulsion applications, presents a review of past modeling efforts, and identifies areas where further research is needed. Among the topics discussed are differences between planar and axisymmetric flows, development versus self-similar regions, the effect of compressibility and the evolution of compressibility corrections, the effect of temperature on jets, and the significance of turbulent Prandtl and Schmidt numbers for reacting shear flows. Large eddy simulation greatly reduces the amount of empiricism in the physical modeling, but is sensitive to a number of numerical issues. This paper includes an overview of the importance of numerical scheme, mesh resolution, boundary treatment, sub-grid modeling, and filtering in conducting a successful simulation. Yoder, Dennis A. and DeBonis, James R. and Georgiadis, Nicolas J. Glenn Research Center TURBULENCE MODELS; AXISYMMETRIC FLOW; FREE FLOW; TURBULENT FLOW; SHEAR FLOW; LARGE EDDY SIMULATION; COMPUTATIONAL FLUID DYNAMICS; MIXING LAYERS (FLUIDS); REYNOLDS AVERAGING; COMPUTATIONAL AEROACOUSTICS; NAVIER-STOKES EQUATION; AEROSPACE ENGINEERING; PROPULSION; PRANDTL NUMBER; SCHMIDT NUMBER; JET AIRCRAFT NOISE

Download or read book Direct Numerical Simulation of Compressible Free Shear Flows written by Sanjiva K. Lele and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeronautical Engineering A Cumulative Index to a Continuing Bibliography supplement 300 written by and published by . This book was released on 1994 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Catalog of United States Government Publications written by United States. Superintendent of Documents and published by . This book was released on 1994 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Aeroacoustics of Complex Flows at Low Mach Number written by Yaser Khalighi and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Designing quiet mechanical systems requires an understanding of the physics of sound generation. Among various sources of noise, aerodynamic sound is the most difficult component to mitigate. In practical applications, aerodynamic sound is generated by complex flow phenomena such as turbulent wakes and boundary layers, separation, and interaction of turbulent flow with irregular solid bodies. In addition, sound waves experience multiple reflections from solid bodies before they propagate to an observer. Prediction of an acoustic field in such configurations requires a general aeroacoustic framework to operate in complex configurations. A general computational aeroacoustics method is developed to evaluate noise generated by low Mach number flow in complex configurations. This method is a hybrid approach which uses Lighthill's acoustic analogy in conjunction with source-data from an incompressible calculation. Flow-generated sound sources are computed by using either direct numerical simulation (DNS) or large eddy simulation (LES); scattering of sound waves are computed using a boundary element method (BEM). In this approach, commonly-made assumptions about the geometry of scattering objects or frequency content of sound are not present, thus it can be applied to a wider range of aeroacoustic problems, where sound is generated by interaction of complex flows with solid surfaces. This new computational technique is applied to a variety of aeroacoustic problems ranging from sound generated by laminar and turbulent vortex shedding from cylinders to realistic configurations such as noise emitted from a rear-view side mirror and a hydrofoil. The purpose of each test case, in addition to validation of the method, is to explore various physical and technical aspects of the problem of sound generation by unsteady flows. Through these test cases, it is demonstrated that the predicted sound field by this technique is accurate in the frequency range in which the sound sources are resolved by the computational mesh. It is also shown that in computation of sound, acoustic analogies are less sensitive to numerical errors than direct computations. Finally, a discussion on the efficacy of LES and the effect of sub-grid scale dynamics on predicted sound is presented.

Download or read book Numerical Simulation of Shear Flows Over Wavy Boundaries written by Steven A. Orszag and published by . This book was released on 1980 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: