Download or read book Characteristics of 3D Turbulent Jets in Crossflow written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-25 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three dimensional turbulent jets in crossflow at low to medium jet-to-crossflow velocity ratios are computed with a finite volume numerical procedure which utilizes a second-moment closure model to approximate the Reynolds stresses. A multigrid method is used to accelerate the convergence rate of the procedure. Comparison of the computations to measured data show good qualitative agreement. All trends are correctly predicted, though there is some uncertainty on the height of penetration of the jet. The evolution of the vorticity field is used to explore the jet-crossflow interaction. Demuren, A. O. Glenn Research Center NASA ORDER C-99066-G...

Download or read book Characteristics of 3D Turbulent Jets in Crossflow written by A. O. Demuren and published by . This book was released on 1991 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characteristics of 3D Turbulent Jets in Crossflow written by A. O. Demuren and published by . This book was released on 1991 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calculation of 3D Turbulent Jets in Crossflow with a Multigrid Method and a Second moment Closure Model written by and published by . This book was released on 1990 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Survey of Literature on Flow Characteristics of a Single Turbulent Jet Impinging on a Flat Plate written by James W. Gauntner and published by . This book was released on 1970 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow characteristics of single jets impinging on flat surfaces have been studied by many investigators. The results of some of the numerous studies are summarized herein. Suggested methods for determining velocities and pressures on which to base heat-transfer correlations for use in impingement cooling design are presented.

Download or read book Multigrid Acceleration and Turbulence Models for Computations of 3D Turbulent Jets in Crossflow written by A. O. Demuren and published by . This book was released on 1991 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulence Characteristics of Counter Flowing Free Jets written by Sayed Fazlolah Saghravani and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets are used in several engineering applications including dilution and mixing. The counter flowing free jet was investigated to find the penetration length and geometry of the expanded jet. The turbulence characteristics of the counter flowing free jets have been determined. Several jet nozzles with different diameters were used to form the jet located at the center of a closed conduit that had a square cross section. The results show that the penetration length varies linearly with the ratio of the jet velocity to the main flow velocity that is denoted by R. Axial and radial velocity components were measured simultaneously using a 2-D laser velocity probe. The raw data was processed and several characteristics of the counter flowing free jets such as the decay rate of the jet and the turbulence behavior of the jet along the jet axis are reported. The turbulent kinetic energy of the counter flowing free jets was studied. Several profiles were chosen and the turbulent kinetic energy was balanced along the radial direction of the jet. The terms including pressure component were used as the closure, since the pressure was not measured. Another major part of the study was to find the wake mixing characteristics of the counter flowing free jets. Several tests with different R values were performed and for each test, the concentration of the tracer injected by the jet to the main flow was measured at several points at different cross sections in the near wake region of the jet. The results show that the mixing between the tracer and the main flow improves with larger jet diameter and bigger velocity ratios. A small part of the study was devoted to numerical test using the software code, Phoenics. Three sets of tests using different turbulence models were performed and the results were compared with the measurement. In comparison, for the case of turbulent jets in counter flow, the k-? model gave a better result than k-? and mixing length models. The results can be applied directly to the control of stream pollution, as the counter flowing free jet is a very effective device to dilute the effluents injected in a stream.

Download or read book Turbulent Jets and Plumes written by Joseph Hun-wei Lee and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets and plumes are shear flows produced by momentum and buoyancy forces. Examples include smokestack emissions, fires and volcano eruptions, deep sea vents, thermals, sewage discharges, thermal effluents from power stations, and ocean dumping of sludge. Knowledge of turbulent mixing by jets and plumes is important for environmental control, impact and risk assessment. Turbulent Jets and Plumes introduces the fundamental concepts and develops a Lagrangian approach to model these shear flows. This theme persists throughout the text, starting from simple cases and building towards the practically important case of a turbulent buoyant jet in a density-stratified crossflow. Basic ideas are illustrated by ample use of flow visualization using the laser-induced fluorescence technique. The text includes many illustrative worked examples, comparisons of model predictions with laboratory and field data, and classroom tested problems. An interactive PC-based virtual-reality modelling software (VISJET) is also provided. Engineering and science students, researchers and practitioners may use the book both as an introduction to the subject and as a reference in hydraulics and environmental fluid mechanics.

Download or read book Interactions of a Fully Modulated Inclined Jet with a Crossflow written by Bertrand P. E. Dano and published by . This book was released on 2006 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets in crossflow are used in a wide range of engineering applications and have been studied for more than 60 years. The transversal penetration and structure of a jet placed in a crossflow is known to be strongly three-dimensional. It is believed that, by using a pulsed jet inclined in the crossflow direction, the momentum transport can be controlled in two very efficient ways: the pulse can increase the jet penetration and the mixing downstream, while the inclination avoids the creation of a reverse flow at the jet exit and may extend the mixing area further downstream. Although some results are available in the literature focusing on components of this problem, none addresses the combination of these two factors. Moreover, most of these studies use elaborate flow visualizations and 2-D velocity measurement methods that may not be adequate to elucidate the complexity of such a flow. This study addresses these issues by using stereoscopic PIV measurements for a steady and fully modulated jet at a constant mean velocity ratio, V[subscript r], of 3.4. For the steady jet case, the effect of the jet Reynolds number, Re[subscript j], is investigated. For the pulsed case, the effect of a low pulsing frequency is considered as well as the pulse duty cycle. For each case, the mean three-component velocity field is examined. Proper Orthogonal Analysis (POD) of vorticity and turbulent kinetic energy are used to further evaluate the vortical and turbulent characteristics of the jet. In addition, a vortex detection algorithm, and 3D rendering of the flow streamlines are used to study the near field vortical flow structure of the jet flow.

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:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Instability Transition and Turbulence written by M.Y. Hussaini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the Workshop on In stability, Transition and Turbulence, sponsored by the Institute for Computer Applications in Science and Engineering (ICASE) and the NASA Langley Research Center (LaRC), during July 8 to August 2, 1991. This is the second workshop in the series on the subject. The first was held in 1989, and its proceedings were published by Springer-Verlag under the title "Instability and Transition" edited by M. Y. Hussaini and R. G. Voigt. The objectives of these work shops are to i) expose the academic community to current technologically im portant issues of transition and turbulence in shear flows over the entire speed range, ii) acquaint the academic community with the unique combination of theoretical, computational and experimental capabilities at LaRC and foster interaction with these capabilities, and iii) accelerate progress in elucidating the fundamental phenomena of transition and turbulence, leading to improved transition and turbulence modeling in design methodologies. The research areas covered in these proceedings include receptiv ity and roughness, nonlinear theories of transition, numerical simu lation of spatially evolving flows, modelling of transitional and fully turbulent flows as well as some experiments on instability and tran sition. In addition a one-day mini-symposium was held to discuss 1 recent and planned experiments on turbulent flow over a backward facing step.

Download or read book Near Field Mixing Characteristics of a Variable Density Non Reacting Jet in a Hot Vitiated Crossflow written by Kyle T Linevitch (Jr) and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mixing characteristics in the "extreme" near field of a non-reacting jet in crossflow were experimentally investigated in an environment relevant to gas turbine combustors. A turbulent jet was injected into a hot vitiated crossflow of combustion products at 1500K. Different jet-to-crossflow momentum flux ratios and jet-to-crossflow density ratios were studied using three different jet exit velocity profiles; a fully developed turbulent pipe flow with 4% turbulence intensity (TI), a top-hat flow with 8% TI, and a turbulent pipe-like flow with 40% TI. Center-plane scalar mixing of the jet and crossflow were investigated using measured temperature fields from planar laser Rayleigh scattering. Jet trajectory, centerline concentration decay, scalar dissipation and mixing time scales were determined as a function of the above-mentioned jet parameters to characterize the jet-crossflow mixing characteristics. The observed center-plane mixing metrics indicated that better near field mixing was exhibited for lower values of the momentum flux ratio and larger values of density ratio. As the momentum flux ratio increased, windward and leeward mixing decreased. The magnitude of scalar dissipation in the windward region decreased as the momentum flux increased, while the leeward dissipation region increased in size and magnitude as momentum flux ratio increased. When the density ratio was decreased, both the windward and leeward dissipation regions reduced in size and magnitude. The top-hat and turbulent pipe jet exit velocity profiles displayed similar mixing characteristics while the 40% TI profile exhibited deeper jet penetration, slower centerline concentration decay rates, and lower scalar dissipation.

Download or read book Challenges of Power Engineering and Environment written by Ke-fa Cen and published by Springer Science & Business Media. This book was released on 2009-03-27 with total page 1432 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the proceedings of the International Conference on Power Engineering-2007. The fields of this book include power engineering and relevant environmental issues. The recent technological advances in power engineering and related areas are introduced. This book is valuable for researchers, engineers and students majoring in power engineering.

Download or read book Institute for Computational Mechanics in Propulsion ICOMP written by Charles E. Feiler and published by . This book was released on 1992 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Jets in Crossing Pipe Flow written by A. M. Ger and published by . This book was released on 1974 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamental Characteristics of Turbulent Opposed Impinging Jets electronic Resource written by Stan, Gheorghe and published by University of Waterloo. This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: