Dense suspensions: force response and jamming

S. von Kann

Research output: ThesisPhD Thesis - Research UT, graduation UT

105 Downloads (Pure)

Abstract

The response of dense suspensions to an external force was studied using two different experiments. In the first experiment, objects were settled in a deep bath of a dense cornstarch suspension. This is the only suspension to result in two unexpected phenomena: Velocity oscillations in the bulk, and stop-go-cycles near the bottom. Both are believed to be caused by a change in the particle configuration within the suspension. In the second experiment, vertical vibrations were exerted to a thin layer of dense suspensions. Depending on suspension and shaking parameters, a lot of different unexpected phenomena were found: Stable and growing holes and fingerlike protrusions, to name a few. All have in common that hydrostatic pressure is overcome, which would normally cause a hole to collapse in any Newtonian liquid, even when vibrated. A convection roll was found on the edge of the holes in the suspensions, which might be explained by a break in symmetry in the oscillations of the hole edge, which in turn can cause a change in particle configuration in the suspension. A cornstarch suspension was found to be a remarkable one. Cornstarch was found to be the only suspension to show non-monotonic settling, and shows the richest phenomenology when shaken. The unique particle properties of the cornstarch, edgy particles with a relatively flat size distribution in the range of 5-20 micrometer, might be the cause of this behavior. No other, easily available, particles were found to have these properties.
Original languageEnglish
Awarding Institution
  • University of Twente
Supervisors/Advisors
  • van der Meer, Devaraj, Supervisor
  • Lohse, Detlef , Advisor
  • Snoeijer, J., Advisor
Award date21 Dec 2012
Place of PublicationEnschede
Publisher
Print ISBNs978-90-365-3471-0
DOIs
Publication statusPublished - 21 Dec 2012

Keywords

  • IR-82720
  • METIS-291125

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