Wall-induced forces on a rigid sphere at finite Reynolds number

Lanying Zeng, S. Balachandar, Paul Fischer

Research output: Contribution to journalArticlepeer-review

Abstract

We perform direct numerical simulations of a rigid sphere translating parallel to a flat wall in an otherwise quiescent ambient fluid. A spectral element method is employed to perform the simulations with high accuracy. For Re < 100, we observe the lift coefficient to decrease with both Reynolds number and distance from the wall. In this regime the present results are in good agreement with the low-Reynolds-number theory of Vasseur & Cox (1977), with the recent experiments of Takemura & Magnaudet (2003) and with the simulations of Kim et al. (t993). The most surprising result from the present simulations is that the wall-induced lift coefficient increases dramatically with increasing Re above about 100. Detailed analysis of the flow field around the sphere suggests that this increase is due to an imperfect bifurcation resulting in the formation of a double-threaded wake vortical structure. In addition to a non-rotating sphere, we also simulate a freely rotating sphere in order to assess the importance of free rotation on the translational motion of the sphere. We observe the effect of sphere rotation on lift and drag forces to be small. We also explore the effect of the wall on the onset of unsteadiness.

Original languageEnglish (US)
Pages (from-to)1-25
Number of pages25
JournalJournal of Fluid Mechanics
Volume536
DOIs
StatePublished - Aug 10 2005
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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