Analysis Of Selected Problems Involving Vortical Flows

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.

This book is a comprehensive and intensive book for graduate students in fluid dynamics as well as scientists, engineers and applied mathematicians. Offering a systematic introduction to the physical theory of vortical flows at graduate level, it considers the theory of vortical flows as a branch of fluid dynamics focusing on shearing process in fluid motion, measured by vorticity. It studies vortical flows according to their natural evolution stages,from being generated to dissipated. As preparation, the first three chapters of the book provide background knowledge for entering vortical flows. The rest of the book deals with vortices and vortical flows, following their natural evolution stages. Of various vortices the primary form is layer-like vortices or shear layers, and secondary but stronger form is axial vortices mainly formed by the rolling up of shear layers. Problems are given at the end of each chapter and Appendix, some for helping understanding the basic theories, and some involving specific applications; but the emphasis of both is always on physical thinking.

A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).

Many important phenomena in fluid motion are evident in vortex flow, i.e., flows in which vortical structures are significant in determining the whole flow. This book, which consists of lectures given at a NATO ARW held in Grenoble (France) in June 1992, provides an up-to-date account of current research in the study of these phenomena by means of numerical methods and mathematical modelling. Such methods include Eulerian methods (finite difference, spectral and wavelet methods) as well as Lagrangian methods (contour dynamics, vortex methods) and are used to study such topics as 2- or 3-dimensional turbulence, vorticity generation by solid bodies, shear layers and vortex sheets, and vortex reconnection. For researchers and graduate students in computational fluid dynamics, numerical analysis, and applied mathematics.

A hierarchal approach for the visualization of complex, three-dimensional vortical flows is presented. This integrated philosophy employs standard and novel visualization techniques to quickly and accurately analyze vortical flows. The hierarchal approach begins by identifying interesting features within the computational domain. Next, these areas of the flow are thoroughly scanned in an attempt to understand the physics which give rise to them. Finally, a variety of extremely interactive probes are used to investigate the finest details of the solution in these regions. Visualization, when approached in this systematic way, is an extremely powerful tool for flow analysis. To aid in understanding of visualization results, the typical features of vortical flows are discussed for a wide range of freestream conditions. The thesis concludes with a detailed visualization of the vortical flow over the National Transonic Facility (NTF) delta wing as calculated by Becker. Using the hierarchal strategy, several interesting flow features including vortex breakdown and vortex sheet instabilities are identified.