In this article we study Galerkin finite element approximations to integral equations of the Volterra type. Our prime concern is the noncoercive case, which is not covered by the standard finite element theory. The question of rates of convergence is studied for the case where an exact stiffness mat
COMPARISON OF H AND P FINITE ELEMENT APPROXIMATIONS OF THE SHALLOW WATER EQUATIONS
โ Scribed by R. A. Walters; E. J. Barragy
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 498 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0271-2091
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โฆ Synopsis
A p-type finite element scheme is introduced for the three-dimensional shallow water equations with a harmonic expansion in time. The wave continuity equation formulation is used which decouples the problem into a Helmholtz equation for surface elevation and a momentum equation for horizontal velocity. An exploration of the applicability of p methods to this form of the shallow water problem is presented, with a consideration of the problem of continuity errors. The convergence rates and relative computational efficiency between h-and p-type methods are compared with the use of three test cases representing various degrees of difficulty. A channel test case establishes convergence rates, a continental shelf test case examines a problem with accuracy difficulties at the shelf break, and a field-scale test case examines problems with highly irregular grids. For the irregular grids, adaptive h combined with uniform p refinement was necessary to retain high convergence rates.
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