Numerical Investigation Of The Origin Of Vortex Asymmetry
DOWNLOAD
Download Numerical Investigation Of The Origin Of Vortex Asymmetry PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Numerical Investigation Of The Origin Of Vortex Asymmetry book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Numerical Investigation Of The Origin Of Vortex Asymmetry
DOWNLOAD
Author : David Degani
language : en
Publisher:
Release Date : 1990
Numerical Investigation Of The Origin Of Vortex Asymmetry written by David Degani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with categories.
A Comprehensive Study Of Vortex Asymmetry On Slender Bodies At High Angles Of Incidence
DOWNLOAD
Author : Roopesh Sampath Kumar
language : en
Publisher:
Release Date : 2021
A Comprehensive Study Of Vortex Asymmetry On Slender Bodies At High Angles Of Incidence written by Roopesh Sampath Kumar and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with Aerospace engineering categories.
Vortex asymmetry develops on slender bodies at high angles of incidence, leading to large side-forcesand yaw moments even in symmetrical flight conditions. This unexpected side force can be large for the control surfaces to produce a restoring moment, thereby affecting the vehicle's trajectory, maneuverability, and performance. Previous studies suggest that the presence of random micro-surface imperfections near the forebody tip, incurred due to the conventional machining process and its coupling with incoming freestream turbulence are the cause for vortex asymmetry. Vortex asymmetry and its control studies have been the subject of numerous experimental and numerical investigations beginning with simplified canonical configurations such as cones and cone-cylinders followed by slender bodies with fins resembling a typical projectile configuration. While previous studies on vortex asymmetry have provided a substantial knowledge base, several fundamental questions about the flow topology and characteristics of the vortices remain unanswered. The key knowledge gaps in the form of a few questions are: what is the effect of aftbody on the initiation and development of vortex asymmetry? What is the role of imperfections on the aftbody, and how do they enhance or suppress vortex asymmetry? What is the role of forebody to aftbody transition junction on vortex initiation and development? How does the forebody vortex-fin interaction alter the control surface effectiveness? To answer some of these questions as research objectives and improve the understanding of flow physics associated with slender bodies at high angles of incidence, a comprehensive experimental and numerical investigation was carried out and the results are presented here. The test configuration involves a long slender body with two interchangeable forebodies (a cone and a tangent ogive). To study the vortex-fin interactions, Army Navy Basic Finner (conecylinder with fins) and ogive-cylinder with fins were designed and tested. Experiments include force measurements using a six-component strain gauge balance, oil flow visualization, velocity and vorticity field measurements using particle image velocimetry. Results show that a pair of counterrotating, nearly-symmetric vortices develop over a polished cone but those become asymmetric over the cylinder. Several secondary shear-layer vortices form at the cone-cylinder junction and over the aftbody due to sharp turn angle (a change on pressure boundary), surface imperfections, and various surface joints. These secondary shear-layer vortices then merge with the primary forebody vortex pair, leading to the flow asymmetry. The flow characteristics and side-forces vary significantly when the conical forebody is rotated about its axis of symmetry and set to different azimuthal positions. The results strongly suggest that a change in the geometry at the cone-cylinder junction and surface imperfections present on the cylindrical aftbody plays a critical role in determining the overall flowasymmetry and the side force magnitude. The effect of forebody change has a significant impact on the flow field development. The peak vorticity, circulation, and trajectory of primary vortices for ogive-cylinder configuration indicate a notable change in both magnitude and location when compared to cone-cylinder configuration. The results show that the formation of secondary shearlayer vortices can be minimized by eliminating the sudden change in geometry and smoothing the surface imperfections. The absence of secondary shear-layer vortices resulted in relatively low levels of side forces for the ogive-cylinder configuration as compared to the cone-cylinder. In the case of vortex-fin interaction investigations, results show that the basic aerodynamic characteristics remain invariant with roll orientation at low angles of incidence. At high angles of incidence, fin orientation plays a significant role in dictating the body's aerodynamic forces. At low angles of incidence, the forebody vortices are symmetric and remain close to the body, and interact with the control surfaces. The forebody vortex interaction seems to be influenced by the body roll orientation. The pressure distributions over the fin surfaces, and in turn, the fins' control effectiveness is significantly affected by the interaction of forebody vortices. At high angles of incidence, the vortices become highly asymmetric, where one vortex is closer to the fins and the other vortex lifted away from the fins. Under such an instance, the resulting pressure distribution is uneven and lead to the generation of side forces and adverse yaw moments. To summarize, the present study has significantly improved the fundamental understanding of vortex flows on slender bodies at high angles of incidence. In particular, it has answered the role of secondary vortices on the development of overall vortex asymmetry and its interaction with control surfaces. The outcome of this study will help guide the design of next-generation projectiles expected to perform maneuvers at high angles of incidence. The high-fidelity experimental database generated over a range of test conditions will be very useful to validate physics based simulation tools being developed at Army Research Laboratory. The present study was focused at low-speeds and incompressible flows and therefore it is suggested that future studies must investigate the effect of compressibility on vortex asymmetry. Also, time-resolved measurements are recommended to understand the role of vortex dynamics on the slender body.
A Numerical Investigation Of A Confined Vortex Problem
DOWNLOAD
Author : Robin E. Textor
language : en
Publisher:
Release Date : 1968
A Numerical Investigation Of A Confined Vortex Problem written by Robin E. Textor and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1968 with Navier-Stokes equations categories.
Vortex Asymmetry Development On A Tangent Ogive
DOWNLOAD
Author : William J. Yanta
language : en
Publisher:
Release Date : 1982
Vortex Asymmetry Development On A Tangent Ogive written by William J. Yanta and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with Angle of attack (Aerodynamics). categories.
Analytical Study Of The Origin And Behavior Of Asymmetric Vortices
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1990
Analytical Study Of The Origin And Behavior Of Asymmetric Vortices written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with categories.
A Numerical Study On Elliptical Instabilities In A Counter Rotating Asymmetric Vortex Pair
DOWNLOAD
Author : Doris Stumps
language : en
Publisher:
Release Date : 2023
A Numerical Study On Elliptical Instabilities In A Counter Rotating Asymmetric Vortex Pair written by Doris Stumps and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.
The elliptical instability in two unequal counter rotating vortices is studied with numerical simulations for a circulation Reynolds number of Re[gamma] =3100. The initially Gaussian vortices with equal and opposite circulation but unequal peak vorticity and core size are subjected to random perturbations, and their time evolution in the linear phases is examined. Asymmetry is achieved by simultaneously increasing core radius and lowering peak vorticity on one vortex while keeping the properties on the other vortex fixed between simulations. The effects of this asymmetry on the interaction between the two vortices are then studied, and it is found that deformation is more prominent on the larger vortex with lower peak vorticity for all simulations due to the higher relative strain it experiences. The most unstable non-dimensional wavenumber increases for increasingly asymmetrical cases; the global growth rate of the most unstable mode is higher in the weakly asymmetrical pair than the symmetrical pair and the strongly asymmetrical pair.
Numerical Investigation Of Vortex Induced Rotation
DOWNLOAD
Author : Veeraraghavan Seshadri
language : en
Publisher:
Release Date : 2003
Numerical Investigation Of Vortex Induced Rotation written by Veeraraghavan Seshadri and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
Numerical Investigation Of Three Dimensional Vortex Breakdown
DOWNLOAD
Author : Keith Vincent Lucas
language : en
Publisher:
Release Date : 1997
Numerical Investigation Of Three Dimensional Vortex Breakdown written by Keith Vincent Lucas and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with categories.
Numerical Simulation Of The Effect Of Spatial Disturbances On Vortex Asymmetry
DOWNLOAD
Author : David Degani
language : en
Publisher:
Release Date : 1989
Numerical Simulation Of The Effect Of Spatial Disturbances On Vortex Asymmetry written by David Degani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1989 with categories.
Theory Of Concentrated Vortices
DOWNLOAD
Author : S. V. Alekseenko
language : en
Publisher: Springer Science & Business Media
Release Date : 2007-08-29
Theory Of Concentrated Vortices written by S. V. Alekseenko and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-08-29 with Technology & Engineering categories.
This book presents comprehensive and authoritative coverage of the wide field of concentrated vortices observed in nature and technique. The methods for research of their kinematics and dynamics are considered. Special attention is paid to the flows with helical symmetry. The authors have described models of vortex structures used for interpretation of experimental data which serve as a ground for development of theoretical and numerical approaches to vortex investigation.