Download or read book Effect of Forcing on the Vorticity Field in a Confined Wake written by Richard Keith Cohn and published by . This book was released on 1999 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Springer Handbook of Experimental Fluid Mechanics written by Cameron Tropea and published by Springer Science & Business Media. This book was released on 2007-10-09 with total page 1570 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accompanying DVD-ROM contains ... "all chapters of the Springer Handbook."--Page 3 of cover.
Download or read book Vorticity Field Evolution in a Forced Wake written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this work is to quantify the vorticity evolution in the flow field of the forced wake of a splitter plate inside a confining geometry. The interest in this flow stems from the fact that forcing a low Reynolds number 2-D wake can lead to a highly three-dimensional flow and a large increase in mixing 1. Our recent estimates, based on chemically reacting LIF measurements, report the amount of molecularly mixed fluid in terms of mixed-fluid fraction to be 2.5 to 3 times larger than that in high Reynolds number natural two-stream mixing layers 2. Both reacting and non-reacting LIF data connect this increase in mixing to the downstream evolution of the streamwise vorticity, which is generated by the reorientation and stretching of spanwise vorticity near the side walls of the flow facility. It is believed that understanding the vorticity interaction with walls, its dynamics, and downstream evolution will be helpful to an overall strategy for mixing enhancement and control.
Download or read book Twenty First Symposium on Naval Hydrodynamics written by National Research Council and published by National Academies Press. This book was released on 1997-09-11 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2012-08-27 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.
Download or read book Streamwise Vorticity in the Transitional Region of a Near Surface Jet written by Lee Thomason and published by . This book was released on 1997 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Visualization written by Alexander J. Smits and published by World Scientific. This book was released on 2012 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the 2nd edition of the book, Flow Visualization: Techniques and Examples, which was published by Imperial College Press in 2000. Many of the chapters have been revised and updated to take into consideration recent changes in a number of flow visualization and measurement techniques, including an updated high quality flow gallery. Unique among similar publications, this book focuses on the practical rather than theoretical aspects. Obtaining high quality flow visualization results is, in many ways, more of an art than a science, and experience plays a key deciding role. The depth and breadth of the material will make this book invaluable to readers of all levels of experience in the field.
Download or read book The Aerodynamics of Heavy Vehicles Trucks Buses and Trains written by Rose McCallen and published by Springer Science & Business Media. This book was released on 2013-07-30 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is our pleasure to present these proceedings from the United Engineering Foundation Conference on The Aerodynamics of Heavy Vehicles: Trucks, Buses and Trains held December 2-6, 2002, in Monterey, California. This Department of Energy, United Engineering Foundation, and industry sponsored conference brought together 90 leading engineering researchers from around the world to discuss the aerodynamic drag of heavy vehicles. Participants from national labs, academia, and industry, including truck manufacturers, discussed how computer simulation and experimental techniques could be used to design more fuel efficient trucks, buses, and trains. Conference topics included comparison of computational fluid dynamics calculations using both steady and unsteady Reynolds-averaged Navier-Stokes, large-eddy simulation, and hybrid turbulence models and experimental data obtained from the Department of Energy sponsored and other wind tunnel experiments. Advanced experimental techniques including three-dimensional particle image velocimetry were presented, along with their use in evaluating drag reduction devices. We would like to thank the UEF conference organizers for their dedication and quick response to sudden deadlines. In addition, we would like to thank all session chairs, the scientific advisory committee, authors, and reviewers for their many hours of dedicated effort that contributed to a successful conference and resulted in this document of the conference proceedings. We also gratefully acknowledge the support received from the United Engineering Foundation, the US Department of Energy, Lawrence Livermore National Laboratory, Volvo Trucks America, International Truck and Engine Corporation, and Freightliner LLC.
Download or read book Experimental Study of the 2 D and 3 D Structure of a Concentrated Line Vortex Array written by Douglas Gordon Bohl and published by . This book was released on 2002 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Longitudinal Wake Vortices written by Linda K. Kliment and published by . This book was released on 2009 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present study, the mid-field vortex wake is investigated. For the most part, the results focus on the motion of a pair of co-rotating vortices prior to merger, both in and out of ground effect. However, in order to verify the experimental and computational methods, results for single vortices, counter-rotating pairs, and complex wakes are also presented. A method is presented which allows measurement of the time dependent motion of vortex filaments. This optical method interferes minimally with the wake and allows recording of vortex location and time-dependent motion. From the position and time information recorded, extraction of the amplitudes of motion, core motion, spiraling behavior, vortex strengths, and the principal planes of motion is possible. First, a single vortex is studied in order to establish a basis for comparison. The dye remains in the core and the motion of a single vortex is shown to exhibit a growth in amplitude with increasing downstream distance and strength. The core motion is shown to be minimal, remaining smaller that one core diameter. In addition, when the single vortex is forced to oscillate at a given frequency, the dye still remains in the core, even though the amplitudes of motion are large. The forcing frequency is identified easily against the background noise. Two four-vortex cases are then presented. The first case consists of filaments that spiral while in the second they scatter. These results are consistent with those shown in literature and show that the experimental method can be used for analyzing complex wakes. Pairs of unforced, co-rotating filaments are studied outside of ground effect. Many cases are presented, some for nearly equal strengths and others in which one vortex is much stronger than the other. As in the single-vortex case, the amplitudes of motion are shown to increase as the downstream distance becomes greater. The constant rate of spiraling is shown to increase as the vortex strength increases and vortex span decreases. Vortex span either remains constant or decreases with downstream distance depending on the vortex separation distance. The motion of the center of spiraling is shown to be minimal, similar to the motion of the vortex core in the single-vortex cases. The filaments are shown to sometimes oscillate along preferred directions, which is inconsistent with a theoretical model developed in 1975. A few cases are also presented in which the merger location is analyzed. However, these are visual investigations only, since it is not possible to obtain quantitative data for such cases with the experimental method available. The behavior of co-rotating vortices in the presence of forcing functions is then presented. The results are compared to the theoretical model developed in 1975 and those published after 2002. However, a direct comparison with analytical results is not possible due to the large scatter in the experimental data. Regardless, the experimental results show that the forced corotating vortices do have an unstable oscillatory motion with growing amplitude. The preferred direction of motion implies the presence of stationary waves. These results contradict those of the analytical model developed in 1975 but agree in nature with those published more recently. Ground effect is then considered for counter-rotating vortices, because there is a wealth of information on this topic in the literature. When counter-rotating vortices are near a ground plane, a lateral drift as well as a rebounding behavior is present. The counter-rotating vortices are shown to have a preferred direction of motion which tends to become parallel to the ground plane. The motion is also shown to have increasing amplitude, although this quantity is slightly reduced by the presence of the ground plane. In addition, ground roughness in the form of streamwise ridges has no affect on the vortex trajectories, within the range of downstream distances observable in these experiments. After comparing the results to those in literature, it is concluded that the experimental method is valid and can be used to study co-rotating vortices in ground effect. Literature lacks information on co-rotating vortices in ground effect. The results in this document show that co-rotating vortices in ground effect have a lateral drift as well as a rebound similar to those of counter-rotating pairs. The resulting motion is similar to that of leapfrogging vortex rings. Preferred directions of motion are present, although no trend can be established. In addition, the amplitudes of motion are reduced slightly by the presence of the ground, just as they are for the counter-rotating vortices. Due to the lack of information on co-rotating vortices in ground effect in the current literature, a comparison is impossible. Therefore, two simple computation efforts are undertaken in order to verify some of the flow features. Using a two-dimensional viscous analysis, limited to laminar flow, it is shown that when co-rotating vortices are placed near a stationary wall, a boundary layer forms on the surface and separates. The secondary vortex released by boundary layer separation leads to rebounding of the primary vortices. In addition to affecting the trajectory, the no-slip boundary also affects the time to vortex merger as well as leading to an elongation of the vorticity contours. Furthermore, this analysis demonstrates that making the strengths of the two vortices differ slightly does not affect the spiraling rate, surface boundary layer separation, or rebound. A second inviscid model is also used to study cases consisting of two vortices of unequal strengths. Having unequal strengths does affect the lateral drift of corotating vortices in ground effect. Also, the center of spiraling shifts towards the stronger vortex. However, the inviscid model shows that the vortex span is unaffected by difference in strengths.
Download or read book Active Flow Control for Maximizing Performance of Spark ignited Stratified Charge Engines written by Alvin Chun Hun Goh and published by . This book was released on 2001 with total page 320 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 Separated Flow Over Bodies of Revolution Using an Unsteady Discrete vorticity Cross Wake written by F. J. Marshall and published by . This book was released on 1974 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2000 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Pressure Field of a Vortex Wake in Ground Effect written by Clinton E. Brown and published by . This book was released on 1975 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ground pressures under a descending pair of vortices, such as might be generated by aircraft either landing or taking off are computed. It is found that as the vortices first approach the ground, only positive pressures are produced; however as the descent continues the high velocity field of the vortices makes itself apparent in dips to sub-atmospheric pressure which lie closely beneath the vortex center. Nevertheless, a substantial positive pressure hill precedes the path of the vortex as it moves laterally in the 'ground effect'. The level of pressures produced is dependent only on the flight speed, lift coefficient and aspect ratio while the length scale of the pressure distribution is proportional to the span. These results may be useful in the development of systems to monitor multiple aircraft take-off and/or landing operations.
Download or read book Rotating Flow written by Peter Childs and published by Elsevier. This book was released on 2010-10-29 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows.Developed over the course of 20 years’ research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries.Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows—which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circulations included to help deepen understanding.Whilst competing resources are weighed down with complex mathematics, this book focuses on the essential equations and provides full workings to take readers step-by-step through the theory so they can concentrate on the practical applications. A detailed yet accessible introduction to rotating flows, illustrating the differences between flows where rotation is significant and highlighting the non-intuitive nature of rotating flow fields Written by world-leading authority on rotating flow, Peter Childs, making this a unique and authoritative work Covers the essential theory behind engineering applications such as rotating discs, cylinders, and cavities, with natural phenomena such as atmospheric and oceanic flows used to explain underlying principles Provides a rigorous, fully worked mathematical account of rotating flows whilst also including numerous practical examples in daily life to highlight the relevance and prevalence of different flow types Concise summaries of the results of important research and lists of references included to direct readers to significant further resources
Download or read book 03 3917 03 4041 written by and published by . This book was released on 2003 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
