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Monday, August 10, 2020 | History

4 edition of Accuracy issues on unstructured grids found in the catalog.

Accuracy issues on unstructured grids

Ian Alejandro Sigal

Accuracy issues on unstructured grids

by Ian Alejandro Sigal

  • 267 Want to read
  • 11 Currently reading

Published by National Library of Canada in Ottawa .
Written in English


Edition Notes

Thesis (M.A.Sc) -- University of Toronto, 2002.

SeriesCanadian theses = -- Th`eses canadiennes
The Physical Object
FormatMicroform
Pagination2 microfiches : negative.
ID Numbers
Open LibraryOL20045366M
ISBN 100612686566
OCLC/WorldCa52193410

Stability and accuracy issues are then discussed, including an overview of energy-stability proofs, von Neumann analysis results, and stability characteristics when the These schemes use an adaptive stencil through an unstructured grid in order to achieve a high-order reconstruction. The adaptive nature of the sten- found in the books.   please let me know if any one has developed a code for 2-D steady state conduction process using unstructured grid August 6, , Here it is the brief contents of my book: A.N. GIL'MANOV METHODS OF ADAPTIVE MESHES IN GAS DYNAMIC PROBLEMS Moscow, Nauka, Publishing Company Fizmatlit, , pp. (ALE) method and high accuracy TVD.

57 on structured grids 39 on unstructured grids ____ * Note the “12” grid converged solution on 4 cases (3 structured for all CD's and 1 unstructured for smallest CD) are not incuded because the definition of VREF results in automatic “pass”. If “12” had converged, we would have – 4 = A detailed discussion of the implementation and the accuracy issues related to the present LGR based on the coupling meshing technology of structured grids and unstructured grids, the finite.

multidisciplinary fields. The generality of unstructured grid methods and their ability to enhance solution accuracy through adaptive procedures have proved to be such a great advantage for these diverse applications that many if not most commercial computational fluid dynamics codes currently rely on the use of unstructured meshes. The development was motivated by the desire of balancing computational efficiency and accuracy by selective and conjunctive use of different numerical techniques. The base framework of the discrete model uses Godunov methods on unstructured triangular grids, but the solution technique emphasizes the use of a high-resolution Riemann solver where.


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Accuracy issues on unstructured grids by Ian Alejandro Sigal Download PDF EPUB FB2

For a smooth hexa grid, a "bad" unstructured algorithm may still reduce to acceptable accuracy, but may not work for the higher demand of irregular grids. Maybe the following reference will give an overview over various methods that have been applied for second-order accuracy on unstructured grids.

The shock-fitting technique for unstructured grids has been successfully extended to the three-dimensional case (Bonfiglioli et al., ).Steady simulations of supersonic and hypersonic flows past three-dimensional bodies are shown in Fig.

Fig. 26 A shows pressure isocontours within three cross-flow planes and over the body of the European Agency IXV vehicle, flying at M ∞ = 24 and A numerical model based upon a second-order upwind finite volume method on unstructured triangular grids is developed for solving shallow water equations.

The HLL approximate Riemann solver is used for the computation of inviscid flux functions, which makes it possible to handle discontinuous by:   A sequence of structured C-type grids is utilized in which each grid represents a uniform refinement in each direction over the previous level.

Two structured-grid codes40, 42 are used, in addition to the unstructured-grid flow solver. For the unstructured flow solver, the cells in the structured mesh are simply divided into by: The Structure of Unstructured Grids and 4, and a hybrid grid generation scheme for gaining accuracy near wells (Flandrin, Borouchaki, and Bennis, ), Figure 5.

applicable for unstructured grids, but is unstable for complex porous flow problems (Farmer, ). The. () On the Accuracy of Polynomial Models in Stochastic Computational Electromagnetics Simulations Involving Dielectric Uncertainties. IEEE Antennas and Wireless Propagation Lett () A Sparse Grid Stochastic Collocation Method for Elliptic Interface Problems.

Takeshi Fujita, Takashi Nakamura, in Parallel Computational Fluid Dynamics4 ACCURACY AND SCALABILITY RESULTS. In Accuracy issues on unstructured grids book section, several applications are shown. We used several systems for evaluating the performance of the parallel unstructured CFD solver, ALPHA cluster (DEC AlphaPC DP MHz) connected with Myrinet, SGI Origin (MIPS R MHz) of.

Notes on accuracy of finite-volume discretization schemes on irregular grids Applied Numerical Mathematics, Vol. 60, No. 3 Comparison of Node-Centered and Cell-Centered Unstructured Finite-Volume Discretizations: Inviscid Fluxes. Jiri Blazek PhD, in Computational Fluid Dynamics: Principles and Applications (Third Edition), Gridless method.

Another discretization scheme, which gained recently some interest, is the gridless method [–].This approach employs only clouds of points for the spatial discretization. It does not require that the points are connected to form a grid as in conventional structured or.

A further example is a two-dimensional shallow water calculation on a rectilinear grid as well as on an unstructured grid. The conservation of mass, momentum and energy is checked, and losses are.

The majority of operations within an FR time-step can be cast as matrix multiplications of the form (27) C ← c 1 A B + c 2 C, where c 1, 2 ∈ R are scalar constants, A is a constant operator matrix, and B and C are row-major state matrices.

Within the taxonomy proposed by Goto et al. the multiplications fall into the block-by-panel (GEBP) category. The specific dimensions of the operator. Notes on accuracy of finite-volume discretization schemes on irregular grids Applied Numerical Mathematics, Vol.

60, No. 3 Comparison of Node-Centered and Cell-Centered Unstructured Finite-Volume Discretizations: Inviscid Fluxes. A new simple fictitious domain method, the algebraic immersed interface and boundary (AIIB) method, is presented for elliptic equations with immersed interface conditions.

This method allows jump conditions on immersed interfaces to be discretized with a good accuracy on a compact stencil. Auxiliary unknowns are created at existing grid locations to increase the degrees of freedom of the.

This paper provides a class of optimal algorithms for the linear algebraic systems arising from direct finite element discretization of the fourth-order equation with different boundary conditions on any polygonal domains that are partitioned by unstructured grids.

grids, and data structures to handle the grid are easy to implement; however, structured grids present poor accuracy if the problem to be solved has curved internal or external boundaries. On the other hand, unstructured grids present more exibility and higher accuracy to represent problems that have curved boundaries; however, the data structures.

J.H.M.J. Bruls et al.: Computing radiative heating on unstructured spatial grids Fig. Comparison of errors in I, J and F computed for the plane-parallel model of the quiet Sun on a.

The tracking method is based on the level-set approach with a restricted dynamic definition range in the vicinity of the fronts. Special attention is drawn to the problem of the classical level-set method, i.e. accuracy issues and topological restrictions.

Accuracy preserving limiter for the high-order finite volume method on unstructured grids Computers & Fluids, Vol.

Efficient dimension-by-dimension higher order finite-volume methods for a Cartesian grid with cell-based refinement. The paper presents a direct comparison of convergence properties of finite volume and discontinuous Galerkin methods of the same nominal order of accuracy. Convergence is evaluated on tetrahedral grids for an advection equation and manufactured solution of Euler equations.

The predictions from air quality models are subject to many sources of uncertainty; among them, grid resolution has been viewed as one that is limited by the availability of computational resources.

A large grid size can lead to unacceptable errors for many pollutants formed via nonlinear chemical reactions.

Further, insufficient grid resolution limits the ability to perform accurate exposure. For complex geometry problems, you will be spending a lot of time modifying the geometry model in order to generate a volume mesh regardless of the methods used, structured or unstructured.

And even after the mesh is generated, the refinement of the mesh will continue till the problem is finally solved.Vol issue 4 articles listing for Numerische Mathematik.

Volume Issue 8 - August Coupled 1D–Quasi-2D Flood Inundation Model with Unstructured Grids water spilling overbank from the river onto the floodplains is computed using a storage cell model discretized into an unstructured triangular grid.

Flow exchange between the one-dimensional river cells and the adjacent floodplain cells or.