Sedimentation of cylindrical particles in a viscoelastic liquid: shape-tilting--颗粒学报PARTICUOLOGY

Wang, J., Bai, R.-y., Lewandowski, C., Galdi, G. P., & Joseph, D. D. (2004). Sedimentation of cylindrical particles in a viscoelastic liquid: shape-tilting. China Particuology, 2(1), 13-18. https://doi.org/10.1016/S1672-2515(07)60014-1

Sedimentation of cylindrical particles in a viscoelastic liquid: shape-tilting

Jing Wang ^a, Run-yuan Bai ^a, Craig Lewandowski ^a, Giovanni P. Galdi ^b, Daniel D. Joseph ^a *

a Department of Aerospace Engineering and Mechanics, University of Minnesota, Minneapolis 55455 MN, USA
b Department of Mechanical Engineering, University of Pittsburgh, Pittsburgh 15261 PA, USA

10.1016/S1672-2515(07)60014-1

Volume 2, Issue 1, February 2004, Pages 13-18

Received 29 December 2003, Accepted 1 February 2004, Available online 27 November 2007.

E-mail: joseph@aem.umn.edu

Highlights

Abstract

Aluminum and Teflon cylindrical particles with flat ends are dropped in aqueous Polyox solutions. The terminal equilibrium orientation of the particles is characterized by the tilt angle, α, formed by the major axis of the cylinder with the horizontal. It is observed that α is a function of the aspect ratio L=L/d, where L is the length and d is the diameter of the cylinder, and that it varies continuously from a certain angle, α₀, to 90°, as L increases toward a value L₀. For a given shape, both α₀ and L₀ depend on the density of the cylinder and the properties of the liquid used. For the particles we have considered the value of L₀ is of the order of 2. This “tilt-angle phenomenon” disappears as soon as the ends of the cylinder are round. Specifically, cylinders of the same density and with the same aspect ratio but with round ends, when dropped in the same polymeric solution will reach a final orientation with α=90°. Therefore, this tilt-angle phenomenon seems to be tightly related to the shape of the particle.

Graphical abstract

Keywords

sedimentation; tilt angle; orientation; viscoelastic liquid

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