Flow Control by Feedback

Flow Control by Feedback
Author: Ole Morten Aamo
Publisher: Springer Science & Business Media
Total Pages: 206
Release: 2013-03-14
Genre: Technology & Engineering
ISBN: 1447138058

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This accessible book pioneers feedback concepts for control mixing. It reviews research results appearing over the last decade, and contains control designs for stabilization of channel, pipe and bluff body flows, as well as control designs for the opposite problem of mixing enhancement.

A Comprehensive Study of Vortex Breakdown Flow Mechanisms: Computational Investigation and Preliminary Control

A Comprehensive Study of Vortex Breakdown Flow Mechanisms: Computational Investigation and Preliminary Control
Author:
Publisher:
Total Pages: 170
Release: 2004
Genre:
ISBN:

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A modified vortex filament method is used to simulate the evolution of the transient formation of vortex breakdown. The method supports previous studies, illustrating that vortex breakdown. The method supports previous studies, illustrating that vortex breakdown is initiated by a negative vorticity gradient which triggers an inviscid self-induction feedback mechanism and when subsequently subjected to viscous effects, results in steady state vortex breakdown. The results of the method are first validated experimentally with numerous past dye flow visualization and particle image velocimetry investigations, and then used to qualitatively investigate the self-induction flow mechanisms during the formative stages of stages of transient breakdown. As a complement to the qualitative investigation, a quantitative analysis is performed, which yields a local and dynamical relationship relating the azimuthal vorticity gradient at a particular location to the curvature of the instantaneous streamline, projected onto the meridional plane, at the same location. This relationship further shows that once radial expansion commences in the region of negative azimuthal vorticity, it continues to expand such that the meridional streamline becomes more curved with time, supporting that the negative vorticity gradient not only initiates the radial expansion, but also, feeds its subsequent growth. On the contrary, in the region of a positive gradient, the streamline continues to flatten fostering radial contraction of the vortex tube, which provides a closure to expansion. In attempt to suppress breakdown in two preliminary control simulations, this positive azimuthal vorticity gradient is then introduced to the vortex flow just prior to breakdown. Results from these control simulations illustrated a temporal and spatial delay in breakdown as well as exhibiting flow behavior associated with complete elimination of breakdown.

Flow Control Techniques and Applications

Flow Control Techniques and Applications
Author: Jinjun Wang
Publisher: Cambridge University Press
Total Pages: 293
Release: 2019
Genre: Science
ISBN: 1107161568

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Master the theory, applications and control mechanisms of flow control techniques.

Flow Control

Flow Control
Author: Mohamed Gad-el-Hak
Publisher: Springer
Total Pages: 552
Release: 1998-01-19
Genre: Science
ISBN:

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The potential benefits of realizing efficient flow-control systems range from saving billions of dollars in fuel costs for land, air and sea vehicles to achieving economically/environmentally more competitive industrial processes involving fluid flows. The understanding of some basic mechanisms in free-shear and wall-bounded turbulence suggests that the taming of turbulence is possible so as to eliminate some of its deleterious effects while enhancing others. Passive as well as active, including reactive, flow-control strategies are covered. Sophisticated reactive control systems heavily relying on parallel computers are envisioned for future practical devices to improve the ability to reduce drag, increase lift, suppress flow-induced noise, enhance mixing and achieve other desired flow-control goals. This book is intended for engineers, physicists, applied mathematicians and graduate students who have an interest in the physics and control of laminar, transitional and turbulent flows. The different contributions are written in a clear, pedagogic style and are designed to attract newcomers to the field. A knowledge of basic fluid dynamics is assumed, and the book should help the reader in navigating through the colossal literature available on flow-control fundamentals and practices.

Vortex Dynamics Theories and Applications

Vortex Dynamics Theories and Applications
Author: Zambri Harun
Publisher: BoD – Books on Demand
Total Pages: 236
Release: 2020-12-09
Genre: Science
ISBN: 183962616X

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The book comprises of different areas in which vortex dynamics is important, its generation, evolution, interactions with other motions, and finally the ways it can be controlled. Vortex characteristics are important in many aspects of our lives, from blood circulation in the arteries to the high-speed jet. Flow control and manipulation of vortices have been used to reduce drag for large tankers resulting in billions of dollars in savings. An effective smoke management system must be put in place for critical areas to ensure the safety of people, for example in a very large shopping complex or a large airport. Advanced computational and cloud-computing facilities have contributed significantly to large-scale simulation projects. Therefore, validations could be performed for larger windows of study so that it can now cover the entire e.g. central business district (CBD) for urban heat island (UHI) study or land-ocean interactions.

Rotating Flow

Rotating Flow
Author: Peter Childs
Publisher: Elsevier
Total Pages: 415
Release: 2010-10-29
Genre: Science
ISBN: 0123820995

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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