An Experimental Investigation of Interactions which Develop Between Adjacent Low Speed, Turbulent, Quasi-two-dimensional Free Jets Impinging Upon a Wall

An Experimental Investigation of Interactions which Develop Between Adjacent Low Speed, Turbulent, Quasi-two-dimensional Free Jets Impinging Upon a Wall PDF Author: Arun Lawrence Warren Bokde
Publisher:
ISBN:
Category : Jets
Languages : en
Pages : 228

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Masters Theses in the Pure and Applied Sciences

Masters Theses in the Pure and Applied Sciences PDF Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1461534747
Category : Science
Languages : en
Pages : 421

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Book Description
Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 34 (thesis year 1989) a total of 13,377 theses titles from 26 Canadian and 184 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 34 reports theses submitted in 1989, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1126

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Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Dynamics of Quasi-two-dimensional Turbulent Jets

Dynamics of Quasi-two-dimensional Turbulent Jets PDF Author: Julien Rémy Dominique Gérard Landel
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The study of quasi-two-dimensional turbulent jets is relevant to chemical reactors, the coking process in oil refinement, as well as rivers flowing into lakes or oceans. In the event of a spillage of pollutants into a river, it is critical to understand how these agents disperse with the flow in order to assess damage to the environment. For such flows, characteristic streamwise and cross-stream dimensions can be much larger than the fluid-layer thickness, and so the flow develops in a confined environment. When the distance away from the discharge location is larger than ten times the fluid-layer thickness, the flow is referred to as a quasi-two-dimensional jet. From experimental observations using dyed jets and particle image velocimetry, we find that the structure of a quasi-two-dimensional jet consists of a high-speed meandering core with large counter-rotating eddies developing on alternate sides of the core. The core and eddy structure is self-similar with distance from the discharge location. The Gaussianity of the cross-stream distribution of the time-averaged velocity is due, in part, to the sinuous instability of the core. To understand the transport and dispersion properties of quasi-two-dimensional jets we use a time-dependent advection--diffusion equation, with a mixing length hypothesis accounting for the turbulent eddy diffusivity. The model is supported by experimental releases of dye in jets or numerical releases of virtual passive tracers in experimentally-measured jet velocity fields. We consider the statistical properties of this flow by releasing and then tracking large clusters of virtual particles in the jet velocity field. The probability distributions of two-point properties (such as the distance between two particles) reveal large streamwise dispersion. Owing to this streamwise dispersive effect, a significant amount of tracers can be transported faster than the speed predicted by a simple advection model. Using potential theory, we determine the flow induced by a quasi-two-dimensional jet confined in a rectangular domain. The streamlines of the induced flow predicted by the theory agree with experimental measurements away from the jet boundary. Finally, we investigate the case of a quasi-two-dimensional particle-laden jet. Depending on the bulk concentration of dense particles, we identify different flow regimes. At low concentrations, the jet features the same core and eddy structure observed without the particles, and thus quasi-two-dimensional jet theory can apply to some extent. At larger concentrations, we observe an oscillating instability of the particle-laden jet.

Shock Wave-Boundary-Layer Interactions

Shock Wave-Boundary-Layer Interactions PDF Author: Holger Babinsky
Publisher: Cambridge University Press
ISBN: 1139498649
Category : Technology & Engineering
Languages : en
Pages : 481

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Book Description
Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.

International Aerospace Abstracts

International Aerospace Abstracts PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 974

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Experimental Study of Submerged Turbulent Twin Jets Interacting with a Free Surface and a Solid Wall

Experimental Study of Submerged Turbulent Twin Jets Interacting with a Free Surface and a Solid Wall PDF Author: Ebenezer Essel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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This thesis presents an experimental investigation of the effects of offset height ratio and boundary condition (free surface and solid wall) on the turbulence characteristics of submerged twin jets issuing from two parallel round nozzles. A particle image velocimetry (PIV) technique was used to conduct two sets of experiments. The first set of experiments focused on twin surface jets at Reynolds number, Re = 4400, separation ratio (G/d = 2.3) and offset heights, 1d, 2d, 3d and 4d from the free surface. The second set of experiments, which was designed based on the main findings of the previous experiment, examined the effects of free surface and wall on the turbulence structure of the twin jets. These experiments were performed at Re = 5000, G/d = 2 and offset heights, 1d, 2d and 4d from the free surface or wall. For the surface jets, the mean velocity and turbulence intensities at the free surface rapidly increased beyond the attachment point by amounts that increases with decreasing offset ratio. Further downstream, the surface transverse turbulence intensities decayed to negligible values while the streamwise turbulence intensities were persistent because of the energy redistribution from the transverse Reynolds normal stress to the tangential (streamwise and spanwise) Reynolds stresses. For both boundary conditions, the attachment length, Reynolds stresses and the spatial extents of the large-scale structures increased with increasing offset ratio. The transition of the twin jets to a single jet was more rapid as offset ratio increases due to the enhanced entrainment and mixing for larger offset ratios. The evolution of the jet farther away from the free surface or wall behaved like a free jet, but the decay rate of the jet interacting with each boundary was substantially reduced in the far field due to confinement effects. The difference between the effects of free surface and wall on the mean velocity, Reynolds stresses and triple velocity correlations were confined to the immediate vicinity of each boundary. The interaction between the large-scale structures and the boundaries were also investigated using various multi-point statistical techniques such as discrete wavelet transform, linear stochastic estimation, swirling strength, joint probability density function and two-point velocity correlations. The results showed that, the wall considerably reduced the spatial coherence of the structures embodied in the transverse auto-correlations compared to those near the free surface.

Applied Mechanics Reviews

Applied Mechanics Reviews PDF Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 636

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AGARD Index of Publications

AGARD Index of Publications PDF Author: North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 418

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A Theoretical and Experimental Investigation of Turbulent Jet Interaction

A Theoretical and Experimental Investigation of Turbulent Jet Interaction PDF Author: Steven Brian Weeks
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 96

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Book Description
The interaction of two impinging plane turbulent jets was investigated for the purpose of understanding the performance of proportional fluid amplifiers and momentum-exchange devices. Velocity and turbulence profiles were measured across and at various distances along the combined jet axis through the use of a constant temperature hot-wire anemometer. Experimentally determined jet deflection angles were found to agree with those predicted in a previous work by the free-streamline theory. The results, which are presented in terms of normalized parameters, show that the jet interaction may be divided into three regions: mixing; transition; and fully developed. A vena-contracta effect was found to exist in the mixing region. A discussion of each of the three regions is presented in detail along with generalizations for similar geometries. (Author).