We consider a Fourier technique combiid with a mapping method to improve the accuracy of pseudospectral differentiation on the iufinite line. The mapping is defined by the function to be differentiated itself.
A Spectral Method for Unbounded Domains
β Scribed by T. Matsushima; P.S. Marcus
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 522 KB
- Volume
- 137
- Category
- Article
- ISSN
- 0021-9991
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β¦ Synopsis
A spectral method for an unbounded domain is presented. Rational basis functions, which are algebraically mapped Legendre functions, are used for expansion in the radial direction of polar coordinates (r, ) or (r, , z). They satisfy the pole condition exactly at the coordinate singularity and their behavior as r Η Θ is suitable for expanding smooth functions which decay algebraically or exponentially as r Η Θ. The method is not stiff when it is applied to initial value problems despite the presence of the coordinate singularity. Solenoidal vector fields are treated efficiently by the toroidal and poloidal decomposition which reduces the number of dependent variables from 3 to 2. Examples include the computation of vortex dynamics in two and three dimensions.
π SIMILAR VOLUMES
Meshless methods have gained popularity in recent years. However, like the finite element method, they do not handle unbounded domains well. Coupling with other techniques more suited to performing this task is problematic, since nodal values on the boundary are fictitious rather than actual. The sc