DEFECT CORRECTION WITH A FULLY COUPLED INEXACT NEWTON METHOD |
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Authors: | Richard W Johnson Paul R McHugh Dana A Knoll |
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Affiliation: | 1. Idaho National Engineering Laboratory, EG &2. G Idaho, Inc , Idaho Falls, Idaho, 83415-3808, USA |
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Abstract: | Abstract We examine the characteristics of a fully coupled inexact Newton method using defect correction to obtain high-order solutions for two problems: natural convection in a square cavity and mixed-convection flow over a backward step. Newton's method produces a linearized system with a Jacobian matrix and a residual vector, each of which can be formed using different discrete operators. Solution accuracy depends on the discretization used for the residuals. Defect correction employs low-order operators for the Jacobian but high-order operators for the residuals. We employ an O(h3) convection operator in the residual vector and upwinding in the Jacobian. We find that defect correction is an efficient and effective way to achieve high-order solutions. |
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