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From h to p efficiently: optimal implementation strategies for explicit time‐dependent problems using the spectral/ hp element method
Author(s) -
Bolis A.,
Cantwell C. D.,
Kirby R. M.,
Sherwin S. J.
Publication year - 2014
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.3909
Subject(s) - discretization , polygon mesh , mathematics , polynomial , time delay and integration , limit (mathematics) , runge–kutta methods , algorithm , numerical integration , numerical analysis , computer science , spectral method , stability (learning theory) , time complexity , mathematical optimization , spectral element method , finite element method , mathematical analysis , geometry , physics , extended finite element method , machine learning , computer vision , thermodynamics
SUMMARY We investigate the relative performance of a second‐order Adams–Bashforth scheme and second‐order and fourth‐order Runge–Kutta schemes when time stepping a 2D linear advection problem discretised using a spectral/ hp element technique for a range of different mesh sizes and polynomial orders. Numerical experiments explore the effects of short (two wavelengths) and long (32 wavelengths) time integration for sets of uniform and non‐uniform meshes. The choice of time‐integration scheme and discretisation together fixes a CFL limit that imposes a restriction on the maximum time step, which can be taken to ensure numerical stability. The number of steps, together with the order of the scheme, affects not only the runtime but also the accuracy of the solution. Through numerical experiments, we systematically highlight the relative effects of spatial resolution and choice of time integration on performance and provide general guidelines on how best to achieve the minimal execution time in order to obtain a prescribed solution accuracy. The significant role played by higher polynomial orders in reducing CPU time while preserving accuracy becomes more evident, especially for uniform meshes, compared with what has been typically considered when studying this type of problem.© 2014. The Authors. International Journal for Numerical Methods in Fluids published by John Wiley & Sons, Ltd.