Sur la stabilité des streaks à grande échelle dans les écoulements de Couette et Poiseuille turbulents

Translated title of the contribution: On the stability of large-scale streaks in turbulent Couette and Poiseulle flows

Junho Park, Yongyun Hwang, Carlo Cossu

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The linear secondary stability of large-scale optimal streaks in turbulent Couette flow at Reτ=52 and Poiseulle flow at Reτ=300 is investigated. The streaks are computed by solving the nonlinear two-dimensional Reynolds-averaged Navier-Stokes equations using an eddy-viscosity model. Optimal initial conditions leading the largest linear transient growth are used, and as the amplitude of the initial vortices increases, the amplitude of streaks gradually increases. Instabilities of the streaks appear when their amplitude exceeds approximately 18% of the velocity difference between walls in turbulent Couette flow and 21% of the centerline velocity in turbulent Poiseuille flow. When the amplitude of the streaks is sufficiently large, the instabilities attain significant growth rates in a finite range of streamwise wavenumbers that shows good agreement with the typical streamwise wavenumbers of the large-scale motions in the outer region.

Original languageFrench
Pages (from-to)1-5
Number of pages5
JournalComptes Rendus - Mecanique
Volume339
Issue number1
DOIs
Publication statusPublished - Jan 2011
Externally publishedYes

Keywords

  • Instability
  • Large-scale streaks
  • Secondary instability
  • Turbulent flow

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials

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