MONOLITHIC ALGEBRAIC MULTIGRID PRECONDITIONERS FOR THE STOKES EQUATIONS

Alexey Voronin, Scott Maclachlan, Luke N. Olson, Raymond S. Tuminaro

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate a novel monolithic algebraic multigrid (AMG) preconditioner for the Taylor-Hood (ℙ2/ℙ1) and Scott-Vogelius (ℙ2/ℙdisc1 ) discretizations of the Stokes equations. The algorithm is based on the use of the lower-order ℙ1 iso2/ℙ1 operator within a defect-correction setting, in combination with AMG construction of interpolation operators for velocities and pressures. The preconditioning framework is primarily algebraic, though the ℙ1 iso2/ℙ1 operator must be provided. We investigate two relaxation strategies in this setting. Specifically, a novel block factorization approach is devised for Vanka patch systems, which significantly reduces storage requirements and computational overhead, and a Chebyshev adaptation of the LSC-DGS relaxation from [54] is developed to improve parallelism. The preconditioner demonstrates robust performance across a variety of two-dimensional and three-dimensional Stokes problems, often matching or exceeding the effectiveness of an inexact block triangular (or Uzawa) preconditioner, especially in challenging scenarios such as elongated-domain problems.

Original languageEnglish (US)
Pages (from-to)A343-A373
JournalSIAM Journal on Scientific Computing
Volume47
Issue number1
DOIs
StatePublished - 2025

Keywords

  • algebraic multigrid
  • LSC-DGS relaxation
  • monolithic multigrid
  • Scott-Vogelius
  • Stokes equations
  • Vanka relaxation

ASJC Scopus subject areas

  • Computational Mathematics
  • Applied Mathematics

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