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Title:Wall-induced forces on a rigid sphere at finite Reynolds number
Author(s):Zeng, Lanying; Balachandar, S.; Fischer, Paul
Subject(s):Fluid mechanics
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-Reynoldsnumber theory of Vasseur & Cox (1977), with the recent experiments of Takemura & Magnaudet (2003) and with the simulations of Kim et al. (1993). 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.
Issue Date:2005
Publisher:Cambridge University Press
Citation Info:Lanying Zeng, S. Balachandar, and Paul Fischer. Wall-induced forces on a rigid sphere at finite Reynolds number. Journal of Fluid Mechanics (2005), vol. 536, pp. 1–25.
Publication Status:published or submitted for publication
Peer Reviewed:is peer reviewed
Rights Information:Copyright owned by Cambridge University Press 2005.
Date Available in IDEALS:2007-06-19
Has Version(s):Previously released as TAM Report 1049.

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