Multigrid convergence of inviscid fixed- and rotary-wing flows

W. B. Tsai, Wen-Wei Lin, C. C. Chieng

Research output: Contribution to journalArticle

57 Scopus citations

Abstract

The affect of multigrid acceleration implemented within an upwind-biased Euler method is presented, and applied to fixed-wing and rotary-wing flows. The convergence of fixed- and rotary-wing computations is shown to be vastly different, and multigrid is shown to be less effective for rotary-wing flows. The flow about a hovering rotor suffers from very slow convergence of the inner blade region, where the flow is effectively incompressible. Furthermore, the vortical wake must develop over several turns before convergence is achieved, whereas for fixed-wing computations the far-field grid and solution have little significance. Results are presented for single mesh and two, three, four, and five level multigrid, and using five levels a reduction in required CPU time of over 80 per cent is demonstrated for rotary-wing computations, but 94 per cent for fixed-wing computations. It is found that a simple V-cycle is the most effective, smoothing in the decreasing mesh density direction only, with a relaxed trilinear prolongation operator.

Original languageEnglish
Pages (from-to)121-140
Number of pages20
JournalInternational Journal for Numerical Methods in Fluids
Volume39
Issue number2
DOIs
StatePublished - 20 May 2002

Keywords

  • Computational fluid dynamics
  • Euler equations
  • Fixed-wing flows
  • Multigrid acceleration
  • Rotary-wing flows
  • Structured grid generation

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