Semidiscrete formulations for transient transport at small time steps

Isaac Harari*, Guillermo Hauke

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Solutions of direct time-integration schemes for transient advection-diffusion-reaction problems that converge in time to conventional semidiscrete formulations may be polluted at small time steps by spurious spatial oscillations. This degradation is not an artifact of the time-marching scheme, but rather a property of the solution of the semidiscrete Galerkin approximation itself. An analogy to steady advection-diffusion-reaction problems with a modified reaction coefficient by the Rothe method of discretizing in time prior to spatial discretization provides an upper bound on the time step for the onset of spatial instability. Spatial stabilization removes this pathology, leading to stabilized implicit time-integration schemes that are free of spurious oscillations at small time steps.

Original languageEnglish
Pages (from-to)731-743
Number of pages13
JournalInternational Journal for Numerical Methods in Fluids
Volume54
Issue number6-8
DOIs
StatePublished - 20 Jul 2007

Keywords

  • Rothe method
  • Semidiscrete advection-diffusion-reaction
  • Small time step oscillation
  • Spatial stabilization

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