Author: Saad RagabPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Direct Numerical Simulation of Instability Waves in a Trailing Vortex
Author: Saad RagabVortex Flows and Related Numerical Methods
Author: J.T. BealePublisher: Springer Science & Business Media
ISBN: 9401581371
Category : Technology & Engineering
Languages : en
Pages : 385
Book Description
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.
Waves on Shear and Vortex Flows and the Stability of the Moore-Saffman Model for a Trailing Wingtip Vortex
Author: Jan FeysPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
"This thesis comprises three papers. In the first, the eigenvalue problem governing the propagation of long nonlinear surface waves is investigated when there is a current u(y) beneath the surface, y being the vertical coordinate. We consider specific velocity profiles such as boundary layer profiles of the Falkner-Skan similarity type, including the Blasius case. The singular solutions of the Rayleigh equation are examined to gain insight about the long wave limit of such solutions.The second paper considers the inviscid linear stability of a trailing vortex using mean flow profiles given by an approximate solution of the Navier-Stokes equations. The axial and tangential velocity profiles obtained from this solution, deduced by Moore and Saffman (1973), agree well with experiments involving wings at slight angles of attack; in particular, they better describe the jet-like and wake-like axial flows near the center of the vortex than does the much-studied similarity solution found by Batchelor (1964). We numerically obtain growth rates for unstable perturbations for different values of n, a wingtip loading parameter. Finally, we study the elliptical modes of instability in a pair of counter-rotating trailing wingtip vortices using the aforementioned Moore-Saffman vortex model. To this end, a direct numerical simulation is performed using a spectral method in cylindrical coordinates developed by Matsushima and Marcus (1997). We obtain growth rates and eigenmodes, several of which suggest the presence of a critical layer singularity in the radial coordinate r. Moreover, we compare our results to those for the Batchelor vortex, which is the model that most recent investigations have employed.As is clear from the above, the subject matter of this thesis is twofold: waves on a shear flow on the one hand and vortex stability on the other. However distinct, both subjects have in common the presence of a critical layer singularity, which has a profound impact on the solutions of the equations governing each flow." --
A Numerical Study of the Effects of Stratification on the Short Wave Instability in a Vortex Pair
Author: Daniel MahoneyInteractions of Tollmien-Schlichting Waves and Dean Vortices
Author: Bart A. SingerPublisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 28
Book Description
Vortex Methods
Author: Georges-Henri CottetPublisher: Cambridge University Press
ISBN: 9780521061704
Category : Science
Languages : en
Pages : 0
Book Description
Vortex methods have matured in recent years, offering an interesting alternative to finite difference and spectral methods for high resolution numerical solutions of the Navier Stokes equations. In the past three decades, research into the numerical analysis aspects of vortex methods has provided a solid mathematical background for understanding the accuracy and stability of the method. At the same time vortex methods retain their appealing physical character, which was the motivation for their introduction. This book presents and analyzes vortex methods as a tool for the direct numerical simulation of impressible viscous flows. It will interest graduate students and researchers in numerical analysis and fluid mechanics and also serve as an ideal textbook for courses in fluid dynamics.
New Results in Numerical and Experimental Fluid Mechanics VI
Author: Cameron TropeaPublisher: Springer Science & Business Media
ISBN: 3540744606
Category : Technology & Engineering
Languages : en
Pages : 487
Book Description
This volume features the contributions to the 15th Symposium of the STAB (German Aerospace Aerodynamics Association). Papers provide a broad overview of ongoing work in Germany, including high aspect ratio wings, low aspect ratio wings, bluff bodies, laminar flow control and transition, active flow control, hypersonic flows, aeroelasticity, aeroacoustics, mathematical fundamentals, numerical simulations, physical fundamentals, and facilities.
Scientific and Technical Aerospace Reports
Author: AIAA Journal
Author: American Institute of Aeronautics and AstronauticsPublisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1184
Book Description
Direct and Large-Eddy Simulation IV
Author: Bernard GeurtsPublisher: Springer Science & Business Media
ISBN: 9401712638
Category : Technology & Engineering
Languages : en
Pages : 543
Book Description
This volume contains the proceedings of the 2001 DLES4 workshop. It describes and discusses state-of-the-art modeling and simulation approaches for complex flows. Fundamental turbulence and modeling issues but also elements from modern numerical analysis are at the heart of this field of interest.