Plane Smoothers for Multiblock Grids PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Plane Smoothers for Multiblock Grids PDF full book. Access full book title Plane Smoothers for Multiblock Grids by Ignacio M. Llorente. Download full books in PDF and EPUB format.
Author: Ignacio M. Llorente
Publisher:
ISBN:
Category :
Languages : en
Pages : 32
Get Book Here
Book Description
Author: Ignacio M. Llorente
Publisher:
ISBN:
Category :
Languages : en
Pages : 32
Get Book Here
Book Description
Author: Nigel P. Weatherill
Publisher: Springer Science & Business Media
ISBN: 3322878813
Category : Technology & Engineering
Languages : en
Pages : 332
Get Book Here
Book Description
Computational Fluid Dynamics research, especially for aeronautics, continues to be a rewarding and industrially relevant field of applied science in which to work. An enthusiastic international community of expert CFD workers continue to push forward the frontiers of knowledge in increasing number. Applications of CFD technology in many other sectors of industry are being successfully tackled. The aerospace industry has made significant investments and enjoys considerable benefits from the application of CFD to its products for the last two decades. This era began with the pioneering work ofMurman and others that took us into the transonic (potential flow) regime for the first time in the early 1970's. We have also seen momentous developments of the digital computer in this period into vector and parallel supercomputing. Very significant advances in all aspects of the methodology have been made to the point where we are on the threshold of calculating solutions for the Reynolds-averaged Navier-Stokes equations for complete aircraft configurations. However, significant problems and challenges remain in the areas of physical modelling, numerics and computing technology. The long term industrial requirements are captured in the U. S. Governments 'Grand Challenge' for 'Aerospace Vehicle Design' for the 1990's: 'Massively parallel computing systems and advanced parallel software technology and algorithms will enable the development and validation of multidisciplinary, coupled methods. These methods will allow the numerical simulation and design optimisation of complete aerospace vehicle systems throughout the flight envelope'.
Author: Ignacio M. Llorente
Publisher:
ISBN:
Category : Anisotropy
Languages : en
Pages : 44
Get Book Here
Book Description
Abstract: "We discuss the behavior of several plane relaxation methods as multigrid smoothers for the solution of a discrete anisotropic elliptic model problem on cell-centered grids. The methods compared are plane Jacobi with damping, plane Jacobi with partial damping, plane Gauss-Seidel, plane zebra Gauss-Seidel, and line Gauss-Seidel. Based on numerical experiments and local mode analysis, we compare the smoothing factor of the different methods in the presence of strong anisotropies. A four-color Gauss-Seidel method is found to have the best numerical and architectural properties of the methods considered in the present work. Although alternating direction plane relaxation schemes are simpler and more robust than other approaches, they are not currently used in industrial and production codes because they require the solution of a two-dimensional problem for each plane in each direction. We verify the theoretical predictions of Thole and Trottenberg that an exact solution of each plane is not necessary and that a single two-dimensional multigrid cycle gives the same result as an exact solution, in much less execution time. Parallelization of the two-dimensional multigrid cycles, the kernel of the three-dimensional implicit solver, is also discussed. Alternating-plane smoothers are found to be highly efficient multigrid smoothers for anisotropic elliptic problems."
Author: Erik Dick
Publisher: Springer Science & Business Media
ISBN: 3642583121
Category : Mathematics
Languages : en
Pages : 306
Get Book Here
Book Description
This volume contains 39 of the papers presented at the Sixth European Multigrid Conference, held in Gent, Belgium, September 27-30, 1999. The topics treated at the conference cover all aspects of Multigrid Methods: theory, analysis, computer implementation, applications in the fields of physics, chemistry, fluid mechanics, structural mechanics and magnetism.
Author: D. Keyes
Publisher: Elsevier
ISBN: 008053838X
Category : Mathematics
Languages : en
Pages : 477
Get Book Here
Book Description
Contributed presentations were given by over 50 researchers representing the state of parallel CFD art and architecture from Asia, Europe, and North America. Major developments at the 1999 meeting were: (1) the effective use of as many as 2048 processors in implicit computations in CFD, (2) the acceptance that parallelism is now the 'easy part' of large-scale CFD compared to the difficulty of getting good per-node performance on the latest fast-clocked commodity processors with cache-based memory systems, (3) favorable prospects for Lattice-Boltzmann computations in CFD (especially for problems that Eulerian and even Lagrangian techniques do not handle well, such as two-phase flows and flows with exceedingly multiple-connected demains with a lot of holes in them, but even for conventional flows already handled well with the continuum-based approaches of PDEs), and (4) the nascent integration of optimization and very large-scale CFD. Further details of Parallel CFD'99, as well as other conferences in this series, are available at http://www.parcfd.org
Author: Jim E. Jones
Publisher:
ISBN:
Category : Anisotropy
Languages : en
Pages : 18
Get Book Here
Book Description
Abstract: "Efficient and robust multigrid solvers for anisotropic problems typically use either semi-coarsened grids or implicit smoothers -- line relaxation in 2D and plane relaxation in 3D. However, both of these may be difficult to implement in codes using multi-block structured grids where there may be no natural definition of a global 'line' or 'plane'. These multi-block structured grids are often used in fluid dynamic applications to capture complex geometries and/or to facilitate parallel processing. In this paper, we investigate the performance of multigrid algorithms using implicit smoothers within the blocks of a such a [sic] grid. By looking at a model problem, the 2-D anisotropic diffusion equation, we show that true multigrid efficiency is achieved only when the block sizes are proportional to the strength of the anisotropy. Further, the blocks must overlap and the size of the overlap must again be proportional to the strength of the anisotropy."
Author:
Publisher:
ISBN:
Category : Mathematical statistics
Languages : en
Pages : 802
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 182
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1144
Get Book Here
Book Description
Author: Ignacio M. Llorente
Publisher:
ISBN:
Category : Boundary value problems
Languages : en
Pages : 36
Get Book Here
Book Description
Multigrid algorithms are known to be highly efficient in solving systems of elliptic equations. However, standard multi grid algorithms fail to achieve optimal grid-independent convergence rates in solving non-elliptic problems. In many practical cases, the non-elliptic part of a problem is represented by the convection operator. Downstream marching, when it is viable, is the simplest and most efficient way to solve this operator. However, in a parallel setting, the sequential nature of marching degrades the efficiency of the algorithm. The aim of this report is to present, evaluate and analyze an alternative highly parallel multi grid method for 3-D convection-dominated problems. This method employs semi coarsening, a four-color plane-implicit smoother, and discretization rules allowing the same cross-characteristic interactions on all the grids involved to be maintained. The resulting multigrid solver exhibits a fast grid-independent convergence rate for solving the convection-diffusion operator on cell-centered grids with stretching. The load imbalance below the critical level is the main source of inefficiency in its parallel implementation. A hybrid smoother that degrades the convergence properties of the method but improves its granularity has been found to be the best choice in a parallel setting. The numerical and parallel properties of the multi grid algorithm with the four-color and hybrid smoothers are studied on SGI Origin 2000 and Cray T3E systems.
