A Fourth Order Dissipation Model for Vortex Dominated Flows
Author : James R. Sirbaugh
Publisher :
Page : pages
File Size : 33,46 MB
Release : 1995
Category :
ISBN :
Author : James R. Sirbaugh
Publisher :
Page : pages
File Size : 33,46 MB
Release : 1995
Category :
ISBN :
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 46 pages
File Size : 42,78 MB
Release : 2018-06-30
Category :
ISBN : 9781722081263
The conservative unsteady Euler equations for the flow relative motion in the moving frame of reference are used to solve for the steady and unsteady flows around sharp-edged delta wings. The resulting equations are solved by using an implicit approximately-factored finite volume scheme. Implicit second-order and explicit second- and fourth-order dissipations are added to the scheme. The boundary conditions are explicitly satisfied. The grid is generated by locally using a modified Joukowski transformation in cross flow planes at the grid chord stations. The computational applications cover a steady flow around a delta wing whose results serve as the initial conditions for the unsteady flow around a pitching delta wing about a large angle of attack. The steady results are compared with the experimental data and the periodic solution is achieved within the third cycle of oscillation. Kandil, Osama A. Unspecified Center NAG1-846...
Author : Sean Javad Kamkar
Publisher : Stanford University
Page : 218 pages
File Size : 44,57 MB
Release : 2011
Category :
ISBN :
A new adaptive mesh refinement strategy that is based on a coupled feature-detection and error-estimation approach is developed. The overall goal is to apply the proper degree of refinement to key vortical features in aircraft and rotorcraft wakes. The refinement paradigm is based on a two-stage process wherein the vortical regions are initially identified for refinement using feature-detection, and then the appropriate resolution is determined by the local solution error. The feature-detection scheme uses a local normalization procedure that allows it to automatically identify regions for refinement with threshold values that are not dependent upon the convective scales of the problem. An error estimator, based on the Richardson Extrapolation method, then supplies the identified features with appropriate levels of refinement. The estimator is shown to be well-behaved for steady-state and time-accurate aerodynamic flows. The above strategy is implemented within the Helios code, which features a dual-mesh paradigm of unstructured grids in the near-body domain, and adaptive Cartesian grids in the off-body domain. A main objective of this work is to control the adaption process so that high fidelity wake resolution is obtained in the off-body domain. The approach is tested on several theoretical and practical vortex-dominated flow-fields in an attempt to resolve wingtip vortices and rotor wakes. Accuracy improvements to rotorcraft performance metrics and increased wake resolution are simultaneously documented.
Author : Aga Myung Goodsell
Publisher :
Page : 48 pages
File Size : 46,41 MB
Release : 1991
Category : Aerodynamics, Supersonic
ISBN :
Author : Lu Ting
Publisher : Springer Science & Business Media
Page : 508 pages
File Size : 28,37 MB
Release : 2007-07-05
Category : Science
ISBN : 3540685820
This monograph provides in-depth analyses of vortex dominated flows via matched and multiscale asymptotics, and demonstrates how insight gained through these analyses can be exploited in the construction of robust, efficient, and accurate numerical techniques. The book explores the dynamics of slender vortex filaments in detail, including fundamental derivations, compressible core structure, weakly non-linear limit regimes, and associated numerical methods. Similarly, the volume covers asymptotic analysis and computational techniques for weakly compressible flows involving vortex-generated sound and thermoacoustics. The book is addressed to both graduate students and researchers.
Author : Osama A. Kandil
Publisher :
Page : pages
File Size : 38,61 MB
Release : 1990
Category : Airplanes
ISBN :
Author : Aga M. Goodsell
Publisher :
Page : 48 pages
File Size : 28,94 MB
Release : 1991
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ISBN :
Author : Matteo Moioli
Publisher :
Page : 0 pages
File Size : 40,69 MB
Release : 2022
Category :
ISBN :
Author : Sharath Girimaji
Publisher : Springer
Page : 481 pages
File Size : 15,17 MB
Release : 2015-02-20
Category : Technology & Engineering
ISBN : 331915141X
This book gathers the proceedings of the Fifth Symposium on Hybrid RANS-LES Methods, which was held on March 19-21 in College Station, Texas, USA. The different chapters, written by leading experts, reports on the most recent developments in flow physics modelling, and gives a special emphasis to industrially relevant applications of hybrid RANS-LES methods and other turbulence-resolving modelling approaches. The book addresses academic researchers, graduate students, industrial engineers, as well as industrial R&D managers and consultants dealing with turbulence modelling, simulation and measurement, and with multidisciplinary applications of computational fluid dynamics (CFD), such as flow control, aero-acoustics, aero-elasticity and CFD-based multidisciplinary optimization. It discusses in particular advanced hybrid RANS-LES methods. Further topics include wall-modelled Large Eddy Simulation (WMLES) methods, embedded LES, and a comparison of the LES methods with both hybrid RANS-LES and URANS methods. Overall, the book provides readers with a snapshot on the state-of-the-art in CFD and turbulence modelling, with a special focus to hybrid RANS-LES methods and their industrial applications.
Author :
Publisher :
Page : 530 pages
File Size : 30,35 MB
Release : 1996
Category : Aeronautics
ISBN :