Three-dimensional Vortex-body Interaction in a Viscous Fluid

Three-dimensional Vortex-body Interaction in a Viscous Fluid
Author: Jeffrey S. Marshall
Publisher:
Total Pages: 50
Release: 1999
Genre: Fluid dynamics
ISBN:

An experimental and computational study of the impact of a vortex with a body oriented normal to the vortex axis was performed. Particular focus was placed on understanding characteristics of the secondary vorticity ejected from the body and the interaction of the secondary vorticity with the primary vortex. Since both onset of boundary layer separation and the form of the secondary vorticity structures are sensitive to variation of the velocity normal to the body axis, the effect of normal velocity on vortex-body interaction was carefully examined. The physical features of the flow evolution were categorized in terms of an impact parameter and a thickness parameter, which respectively represent ratios of velocity and length scales associated with the vortex to those associated with the flow in the absence of the vortex. Experiments were performed using a combination of laser-induced fluorescence (LIF) flow visualization and particle-image velocimetry (PIV) in a water tank to examine the form of the secondary vorticity structures with both "high" and "low" values of the impact parameter for normal vortex interaction with a circular cylinder and with a thin blade. A new type of Lagrangian vorticity method based on a tetrahedral mesh was developed and applied to compute the secondary vorticity evolution during vortex-cylinder interaction. Computations were also performed for model problems to examine in detail wrapping of a vortex loop around a columnar vortex and impulsive cutting of a columnar vortex with finite axial flow.

Vorticity and Vortex Dynamics

Vorticity and Vortex Dynamics
Author: Jie-Zhi Wu
Publisher: Springer Science & Business Media
Total Pages: 776
Release: 2007-04-20
Genre: Technology & Engineering
ISBN: 3540290281

This book is a comprehensive and intensive monograph for scientists, engineers and applied mathematicians, as well as graduate students in fluid dynamics. It starts with a brief review of fundamentals of fluid dynamics, with an innovative emphasis on the intrinsic orthogonal decomposition of fluid dynamic process, by which one naturally identifies the content and scope of vorticity and vortex dynamics. This is followed by a detailed presentation of vorticity dynamics as the basis of later development. In vortex dynamics part the book deals with the formation, motion, interaction, stability, and breakdown of various vortices. Typical vortex structures are analyzed in laminar, transitional, and turbulent flows, including stratified and rotational fluids. Physical understanding of vertical flow phenomena and mechanisms is the first priority throughout the book. To make the book self-contained, some mathematical background is briefly presented in the main text, but major prerequisites are systematically given in appendices. Material usually not seen in books on vortex dynamics is included, such as geophysical vortex dynamics, aerodynamic vortical flow diagnostics and management.

Three-Dimensional Attached Viscous Flow

Three-Dimensional Attached Viscous Flow
Author: Ernst Heinrich Hirschel
Publisher: Springer Science & Business Media
Total Pages: 396
Release: 2013-10-29
Genre: Technology & Engineering
ISBN: 3642413781

Viscous flow is treated usually in the frame of boundary-layer theory and as two-dimensional flow. Books on boundary layers give at most the describing equations for three-dimensional boundary layers, and solutions often only for some special cases. This book provides basic principles and theoretical foundations regarding three-dimensional attached viscous flow. Emphasis is put on general three-dimensional attached viscous flows and not on three-dimensional boundary layers. This wider scope is necessary in view of the theoretical and practical problems to be mastered in practice. The topics are weak, strong, and global interaction, the locality principle, properties of three-dimensional viscous flow, thermal surface effects, characteristic properties, wall compatibility conditions, connections between inviscid and viscous flow, flow topology, quasi-one- and two-dimensional flows, laminar-turbulent transition and turbulence. Though the primary flight speed range is that of civil air transport vehicles, flows past other flying vehicles up to hypersonic speeds are also considered. Emphasis is put on general three-dimensional attached viscous flows and not on three-dimensional boundary layers, as this wider scope is necessary in view of the theoretical and practical problems that have to be overcome in practice. The specific topics covered include weak, strong, and global interaction; the locality principle; properties of three-dimensional viscous flows; thermal surface effects; characteristic properties; wall compatibility conditions; connections between inviscid and viscous flows; flow topology; quasi-one- and two-dimensional flows; laminar-turbulent transition; and turbulence. Detailed discussions of examples illustrate these topics and the relevant phenomena encountered in three-dimensional viscous flows. The full governing equations, reference-temperature relations for qualitative considerations and estimations of flow properties, and coordinates for fuselages and wings are also provided. Sample problems with solutions allow readers to test their understanding.

Three-Dimensional Vortex Interactions in Turbulent Boundary Layers

Three-Dimensional Vortex Interactions in Turbulent Boundary Layers
Author: C. R. Smith
Publisher:
Total Pages: 99
Release: 1985
Genre:
ISBN:

A combined analytical experimental program, which has as its continuing objective the detailed investigation of the three dimensional vortex interactions which take place in turbulent boundary layers, is described and the accomplishments detailed. The analytical and numerical studies have examined both the development and characteristics of loop and hairpin vortices in both uniform and shear flows; particular attention has been paid to the strong three dimensional, inviscid viscous interaction of these types of vortical flow structures with wall region fluid. The experimental studies have focussed on the creation & detailed examination of three dimensional hairpin vortices, developing flow visualization patterns for cross-comparison with both the analytical studies and fully turbulent boundary layer flows. A technique for developing quantitative data by image processing of the visualization patterns is also described. Keywords: Turbulent boundary layer; Coherent structure; Flow visualization; Numerical modelling; Vortex wall interactions; Computer aided analysis; Loop vortices; Hairpin vortices.

Fluid Vortices

Fluid Vortices
Author: Beverley Green
Publisher: Springer Science & Business Media
Total Pages: 916
Release: 1995-03-31
Genre: Technology & Engineering
ISBN: 9780792333760

Fluid Vortices is a comprehensive, up-to-date, research-level overview covering all salient flows in which fluid vortices play a significant role. The various chapters have been written by specialists from North America, Europe and Asia, making for unsurpassed depth and breadth of coverage. Topics addressed include fundamental vortex flows (mixing layer vortices, vortex rings, wake vortices, vortex stability, etc.), industrial and environmental vortex flows (aero-propulsion system vortices, vortex-structure interaction, atmospheric vortices, computational methods with vortices, etc.), and multiphase vortex flows (free-surface effects, vortex cavitation, and bubble and particle interactions with vortices). The book can also be recommended as an advanced graduate-level supplementary textbook. The first nine chapters of the book are suitable for a one-term course; chapters 10--19 form the basis for a second one-term course.

Vortex Dynamics

Vortex Dynamics
Author: P. G. Saffman
Publisher: Cambridge University Press
Total Pages: 332
Release: 1995-02-24
Genre: Mathematics
ISBN: 9780521477390

Vortex dynamics is a natural paradigm for the field of chaotic motion and modern dynamical system theory. However, this volume focuses on those aspects of fluid motion that are primarily controlled by the vorticity and are such that the effects of the other fluid properties are secondary.

Vortex Methods: Selected Papers Of The First International Conference On Vortex Methods

Vortex Methods: Selected Papers Of The First International Conference On Vortex Methods
Author: Kyoji Kamemoto
Publisher: World Scientific
Total Pages: 228
Release: 2000-05-11
Genre: Technology & Engineering
ISBN: 9814493287

Vortex methods have been developed and applied to many kinds of flows related to various problems in wide engineering and scientific fields. The purpose of the First International conference on Vortex methods was to provide an opportunity for engineers and scientists to present their achievements, exchange ideas and discuss new developments in mathematical and physical modeling techniques and engineering applications of vortex methods.

Vortex Dynamics and Vortex Methods

Vortex Dynamics and Vortex Methods
Author: Christopher Radcliff Anderson
Publisher: American Mathematical Soc.
Total Pages: 776
Release: 1991-12-23
Genre: Science
ISBN: 9780821896969

Understanding vortex dynamics is the key to understanding much of fluid dynamics. For this reason, many researchers, using a great variety of different approaches--analytical, computational, and experimental--have studied the dynamics of vorticity. The AMS-SIAM Summer Seminar on Vortex Dynamics and Vortex Methods, held in June 1990 at the University of Washington in Seattle, brought together experts with a broad range of viewpoints and areas of specialization. This volume contains the proceedings from that seminar. The focus here is on the numerical computation of high Reynolds number incompressible flows. Also included is a smaller selection of important experimental results and analytic treatments. Many of the articles contain valuable introductory and survey material as well as open problems. Readers will appreciate this volume for its coverage of a wide variety of numerical, analytical, and experimental tools and for its treatment of interesting important discoveries made with these tools.

Numerical Study on Cut-and-connect of Three Dimensional Vortex Tubes

Numerical Study on Cut-and-connect of Three Dimensional Vortex Tubes
Author: H. L. Chen
Publisher:
Total Pages: 68
Release: 1991
Genre: Vortex motion
ISBN:

In the present study, generation of two vortex rings and their cut-and-connect process were numerically simulated by solving three-dimensional and time-dependent Navier-Stokes equations, under conditions similar to the laboratory experiment. In order to explain the mechanism of cut-and-connect, velocity, vorticity, pressure, helicity density and energy dissipation were examined for the flow field of the cut-and-connect of vortex rings. The present study revealed that energy dissipation is an essential process for circulation cancellation during vortex tubes cutting. Based on this energy dissipation mechanism, it is concluded that the cut-and-connect of vortex tubes may occur in the limit of inviscid flows. This conclusion is particularly important to the three-dimensional discrete vortex method for computing high Reynolds number flows. Features of helicity in the three-dimensional flow field of cut-and-connect process of vortex tubes were also investigated. The relation between the helicity density and the energy dissipation function in the three-dimensional flow field was examined.