Download or read book Entrainment Processes for a Jet in Cross Flow written by and published by . This book was released on 2020 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: A jet in cross flow (JICF) is examined experimentally by injecting a stream of air into crossing fluid with an aim into quantifying entrainment process and downstream evolution. The behavior of JICF is important to fields ranging from turbine-blade cooling to smokestack pollution and volcanic eruption dynamics. Existing simplified volcanic plume models are tested; most importantly, the near-field contributions of complex interconnected vortex systems, which present significant uncertainties because they assume negligible turbulence. While jets in irrotational cross-flow have been investigated, this analysis has focused on the interaction between a turbulent jet in low and highly turbulent cross-flow created by an active grid. Instantaneous velocity fields were collected over seven planes using particle image velocimetry (PIV). A center-plane (x-y) and six planes parallel to the floor (x-z) highlight the interaction and resulting vortex systems. Various jet-to-cross-flow velocity ratios, Rv, were collected for each plane, which allow for computation of mean statistics and Reynolds stresses. Analysis was focused in five stages: a) identification of differences in the development of the jet across various inflow conditions, b) analysis of the vortex systems through transport and critical points analysis, c) decomposition of the flow structures to identify and remove the highest-order contributions to turbulence kinetic energy and d) extraction of reduced order modeling closure terms and e) optimization of closure terms for the simplified one-dimensional model, Plumeria. These five stages provided a comprehensive description of the role of cross-flow turbulence on the development of JICF. Noteworthy findings include significant changes in wake recovery and the near-wake recirculation region that impacted near-field entrainment; increased entrainment for high cross-flow turbulence after the collapse of the potential core due to increased engulfment and viscous nibbling between turbulent fluids; the presence of shear layer and wake vortices through critical point analysis; and the absence of entrainment and shear layer expansion near the exit. Most importantly, the negligible entrainment near the exit and impact of small scale turbulent features that must be included for any specific model to yield reasonable predictions is highlighted. By laying the foundation for a more nuanced approach to JICF, it is possible to more precisely summarize the complex features observed in this work through simplified descriptions that can be of benefit to both engineering design and geophysical modeling.
Download or read book Analysis of an Entrainment Model of the Jet in a Crossflow written by H. S. Chang and published by . This book was released on 1972 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Entrainment of a Hot Jet in a Crossflow written by Jin Tso and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of the Injection of a Heated Turbulent Jet Into a Cross Flow written by James Franklin Campbell and published by . This book was released on 1973 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation has been undertaken to develop a theoretical model of the incompressible jet injection process. The discharge of a turbulent jet into a cross flow was mathematically modeled by using an integral method which accounts for natural fluid mechanisms such as turbulence, entrainment, buoyancy, and heat transfer. The analytical results are supported by experimental data and demonstrate the usefulness of the theory for estimating the trajectory and flow properties of the jet for a variety of injection conditions. The capability of predicting jet flow properties, as well as two- and three- dimensional jet paths, was enhanced by obtaining the jet cross-sectional area during the solution of the conservation equations (a number of previous studies assume a specific growth for the area). Realistic estimates of temperature in the jet fluid were acquired by accounting for heat losses in the jet flow due to forced convection and to entrainment of free-stream fluid into the jet.
Download or read book Manipulation and Control of Jets in Crossflow written by Ann R. Karagozian and published by Springer. This book was released on 2014-05-04 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamental Non-Reactive Jets in Crossflow and Other Jet Systems; Background on Modeling, Dynamical Systems, and Control; Reactive Jets in Crossflow and Multiphase Jets; Controlled Jets in Crossflow and Control via Jet Systems;
Download or read book The Entrainment and Mixing of a Round Buoyant Turbulent Jet in Cross flow written by David Charles Thoman (Jr) and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis summaries the results of an experimental investigation of the near-field behavior and physics of the round buoyant turbulent jet in crossflow. In particular, the study centers on the physics associated with entrainment and mixing phenomena of the jet with the goal of better understanding the trends of trajectory and dilution behavior. The experiments involved a downward discharge of cold nitrogen gas (at about $-$85$spcirc$C) from a cylindrical structure placed in a wind tunnel of horizontally flowing ambient air. The jet was mapped using thermocouple measurements. For the purpose of studying jet/crossflow and jet/wake interactions, fog-oil smoke was used to mark parcels of fluid in the crossflow upstream of the jet and in the wake flow downstream of the discharge structure. Time-averaged, smoke concentrations were gathered through an aspirated sampling probe in conjunction with a calibrated, optical aerosol monitor. Smoke distributions were also photographed. Experiments were performed for four different values for the crossflow-to-exit velocity ratio k, namely, k = 0.7, 1.3, 2.1, and 3.5. The results of the experiments yield a comprehensive picture of the near-field flow patterns, flow interactions, and flow-transport physics for a buoyant jet in crossflow. Key, phenomenologically distinct zones of flow which comprise the near-exit structure of the jet are identified. The flow patterns within these zones, and thus the structure of the near-exit jet, are found to be extremely dependent on the value of the velocity ratio. Flow interactions in this region establish flow patterns which have a pronounced influence on the downstream development of the jet. A method is developed to fully document the trajectory and dilution behavior of the jet with the key parameters of influence. Trajectory and dilution are found to correlate with two parameters, namely, the velocity ratio and the density-difference ratio. Finally, unsteady, large-scale mixing motions within the near-exit flow zones are documented. Distinct modes of large-scale mixing which are responsible for the rapid and extensive dispersion observed in the jet are revealed by this study.
Download or read book Flow Control Techniques and Applications written by Jinjun Wang and published by Cambridge University Press. This book was released on 2018-12-13 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master the theory, applications and control mechanisms of flow control techniques.
Download or read book Fluid Mechanics and Fluid Power Contemporary Research written by Arun K. Saha and published by Springer. This book was released on 2016-09-20 with total page 1638 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume comprises the proceedings of the 42nd National and 5th International Conference on Fluid Mechanics and Fluid Power held at IIT Kanpur in December, 2014.The conference proceedings encapsulate the best deliberations held during the conference. The diversity of participation in the conference, from academia, industry and research laboratories reflects in the articles appearing in the volume. This contributed volume has articles from authors who have participated in the conference on thematic areas such as Fundamental Issues and Perspectives in Fluid Mechanics; Measurement Techniques and Instrumentation; Computational Fluid Dynamics; Instability, Transition and Turbulence; Turbomachinery; Multiphase Flows; Fluid‐Structure Interaction and Flow‐Induced Noise; Microfluidics; Bio‐inspired Fluid Mechanics; Internal Combustion Engines and Gas Turbines; and Specialized Topics. The contents of this volume will prove useful to researchers from industry and academia alike.
Download or read book Volcanic Plumes written by R. S. J. Sparks and published by . This book was released on 1997-09-16 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volcanic plumes, made up of material that has explosively erupted from a volcano, are of fundamental importance to volcanology because their deposits record the past activity of a volcano. They also pose a wide range of hazards to humans and can have significant environmental effects. This book integrates observation, theory, and experimental studies and contains recent research ideas and results.
Download or read book Visualization of Conventional and Combusting Subsonic Jet Instabilities written by Victor V. Kozlov and published by Springer. This book was released on 2015-11-30 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on new information obtained on free microjets, this book explains the latest phenomena in flame evolution in the presence of a transverse acoustic field with round and plane propane microjet combustion. It gives an overview of recent experimental results on instability and dynamics of jets at low Reynolds numbers and provides the reader, step by step, with the milestones and recent advances in jet flow stability and combustion. Readers will also discover a clarification of the differences between top-hat and parabolic round and plane jet instability. Chapters demonstrate features of the interaction between jet and crossflow, and how experimental data testify to similarities of the perturbed flow patterns of laminar and turbulent round jets. A similar response of the jets to external acoustic oscillations is shown, as well as the peculiarities of the effect of a transverse acoustic field on downstream evolution of round and plane macro- and microjets. Basic features of round and plane, macro and micro jets' evolution affected by initial conditions at the nozzle outlet and by environmental perturbations are highlighted. Students of fluid mechanics will gain a solid foundation in hydrodynamic stability and combustion of subsonic jet flow and researchers will value the presentation of special aspects of instability and transition. The work treats both theoretical and practical facets, and it includes supplementary material such as PowerPoint multimedia notes based on results of laboratory scientific experiments.
Download or read book Analysis of a Jet in a Subsonic Crosswind written by and published by . This book was released on 1969 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of a Turbulent Jet in a Cross Flow written by David Kenneth Mosher and published by . This book was released on 1970 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interference phenomenon occurring when a subsonic turbulent jet exhausts normally from a large flat plate into a low speed crossflow was experimentally investigated in the Georgia Tech nine foot wind tunnel. Static pressures were measured on the surface around the jet. In the region off the surface, including the jet plume, wake and surrounding areas, the average total and static pressures and the average velocity magnitudes and directions were determined. Three jet exit configurations were studied, one circular and two slot-shaped with width to length ratios of 0.3 and 3.4. All have the same exit area. The effective jet to cross-flow velocity ratio was varied, for each of the exit configurations, over the range 4.0 to 12.0. Analysis of the data indicates that the pressure distributions induced on the surface are a combined result of the jet's blocking and entraining effects on the cross flow with entrainment becoming the more dominant of the two as the effective velocity ratio is increased. This relative dominance brings about an attenuation of total interference lift loss (when computed as a fraction of gross thrust) primarily by causing a rise in the low pressures in the wake region as the effective velocity ratio increases. When the effective velocity ratio is held fixed, the total interference lift loss increases with increasing width to length ratio of the jet exit. (Author).
Download or read book Recent Research Advances in the Fluid Mechanics of Turbulent Jets and Plumes written by P.A. Davies and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Challenging problems involvrllg jet and plume phenomena are common to many areas of fundamental and applied scientific research, and an understanding of plume and jet behaviour is essential in many geophysical and industrial contexts. For example, in the field of meteorology, where pollutant dispersal takes place by means of atmospheric jets and plumes formed either naturally under conditions of convectively-driven flow in the atmospheric boundary layer, or anthropogenically by the release of pollutants from tall chimneys. In other fields of geophysics, buoyant plumes and jets are known to play important roles in oceanic mixing processes, both at the relatively large scale (as in deep water formation by convective sinking) and at the relatively small scale (as with plume formation beneath ice leads, for example). In the industrial context, the performances of many engineering systems are determined primarily by the behaviour of buoyant plumes and jets. For example, (i) in sea outfalls, where either sewage or thermal effluents are discharged into marine and/or freshwater environments, (ii) in solar ponds, where buoyant jets are released under density interfaces, (iii) in buildings, where thermally-generated plumes affect the air quality and ventilation properties of architectural environments, (iv) in rotating machinery where fluid jet~ are used for cooling purposes, and (v) in long road and rail tunnels, where safety and ventilation prcedures rely upon an understanding of the behaviour of buoyant jets. In many other engineering and oceanographic contexts, the properties of jets and plumes are of great importance.
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 Experiments on Confined Turbulent Jets in Cross Flow written by Yasuhiro Kamotani and published by . This book was released on 1974 with total page 86 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 1990 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrodynamics Theory and Applications written by A. T. Chwang and published by Taylor & Francis Group. This book was released on 1996 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
