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Piecewise Polynomial Mapping Method and Corresponding WENO Scheme withImproved Resolution
Published online by Cambridge University Press: 23 November 2015
Abstract
Abstract. The method of mapping function was first proposed by Henrick et al. [J.Comput. Phys. 207:542-547 (2005)] to adjust nonlinear weights in [0,1] for thefifth order WENO scheme, and through which the requirement of convergence orderis satisfied and the performance of the scheme is improved. Different fromHenrick’s method, a concept of piecewise polynomial function isproposed in this study and corresponding WENO schemes are obtained. Theadvantage of the new method is that the function can have a gentle profile atthe location of the linear weight (or the mapped nonlinear weight can be closeto its linear counterpart), and therefore is favorable for the resolutionenhancement. Besides, the function also has the flexibility of quick convergenceto identity mapping near two endpoints of [0,1], which is favorable for improvednumerical stability. The fourth-, fifth- and sixth-order polynomial functionsare constructed correspondingly with different emphasis on aforementionedflatness and convergence. Among them, the fifth-order version has the flattestprofile. To check the performance of the methods, the 1-D Shu-Osher problem, the2-D Riemann problem and the double Mach reflection are tested with thecomparison of WENO-M, WENO-Z and WENO-NS. The proposed new methods show the bestresolution for describing shear-layer instability of the Riemann problem, andthey also indicate high resolution in computations of double Mach reflection,where only these proposed schemes successfully resolved the vortex-pairingphenomenon. Other investigations have shown that the single polynomial mappingfunction has no advantage over the proposed piecewise one, and it is of noevident benefit to use the proposed method for the symmetric fifth-order WENO.Overall, the fifth-order piecewise polynomial and corresponding WENO scheme aresuggested for resolution improvement.
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- Copyright © Global-Science Press 2015
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