Accuracy of Gradient Reconstruction on Grids with High Aspect Ratio
- Author
- Thomas, James
- Published
- December 2008.
- Physical Description
- 1 electronic document
Online Version
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Free-to-read Unrestricted online access - Summary
- Gradient approximation methods commonly used in unstructured-grid finite-volume schemes intended for solutions of high Reynolds number flow equations are studied comprehensively. The accuracy of gradients within cells and within faces is evaluated systematically for both node-centered and cell-centered formulations. Computational and analytical evaluations are made on a series of high-aspect-ratio grids with different primal elements, including quadrilateral, triangular, and mixed element grids, with and without random perturbations to the mesh. Both rectangular and cylindrical geometries are considered; the latter serves to study the effects of geometric curvature. The study shows that the accuracy of gradient reconstruction on high-aspect-ratio grids is determined by a combination of the grid and the solution. The contributors to the error are identified and approaches to reduce errors are given, including the addition of higher-order terms in the direction of larger mesh spacing. A parameter GAMMA characterizing accuracy on curved high-aspect-ratio grids is discussed and an approximate-mapped-least-square method using a commonly-available distance function is presented; the method provides accurate gradient reconstruction on general grids. The study is intended to be a reference guide accompanying the construction of accurate and efficient methods for high Reynolds number applications
- Other Subject(s)
- Collection
- NASA Technical Reports Server (NTRS) Collection.
- Note
- Document ID: 20090007493.
LF99-8199.
NIA Report No. 2008-12. - Terms of Use and Reproduction
- No Copyright.
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