Nonmonotonic settling of a sphere in a cornstarch suspension.

Cornstarch suspensions exhibit remarkable behavior. Here, we present two unexpected observations for a sphere settling in such a suspension: In the bulk of the liquid the velocity of the sphere oscillates around a terminal value, without damping. Near the bottom the sphere comes to a full stop, but then accelerates again toward a second stop. This stop-go cycle is repeated several times before the object reaches the bottom. We show that common shear thickening or linear viscoelastic models cannot account for the observed phenomena, and propose a minimal jamming model to describe the behavior at the bottom.

[1]  H. A. Barnes,et al.  Shear‐Thickening (“Dilatancy”) in Suspensions of Nonaggregating Solid Particles Dispersed in Newtonian Liquids , 1989 .

[2]  G. McKinley,et al.  The effects of viscoelasticity on the transient motion of a sphere in a shear-thinning fluid , 1997 .

[3]  J. Pinton,et al.  Velocity measurement of a settling sphere , 2000 .

[4]  J. L. Willett.  Packing Characteristics of Starch Granules , 2001 .

[5]  D. Goldman,et al.  Persistent holes in a fluid. , 2003, Physical review letters.

[6]  Detlef Lohse,et al.  Granular physics: Creating a dry variety of quicksand , 2004, Nature.

[7]  Xin Zhang,et al.  A laboratory observation of the surface temperature and velocity distributions on a wavy and windy air–water interface , 2004 .

[8]  E. Flekkøy,et al.  Erratum: Grains and gas flow: Molecular dynamics with hydrodynamic interactions [Phys. Rev. E 61, 4054 (2000)] , 2006 .

[9]  Andrew Belmonte,et al.  Impact dynamics of a solid sphere falling into a viscoelastic micellar fluid , 2006 .

[10]  Daniel Bonn,et al.  Shear thickening of cornstarch suspensions as a reentrant jamming transition. , 2007, Physical review letters.

[11]  M. Sano,et al.  Expanding holes driven by convectionlike flow in vibrated dense suspensions. , 2009, Physical review. E, Statistical, nonlinear, and soft matter physics.

[12]  E. Brown,et al.  Dynamic jamming point for shear thickening suspensions. , 2008, Physical review letters.

[13]  N. Wagner,et al.  Shear thickening in colloidal dispersions , 2009 .

[14]  Jun Zhang,et al.  Focused force transmission through an aqueous suspension of granules. , 2010, Physical review letters.

[15]  É. Clément,et al.  Mesoscopic length scale controls the rheology of dense suspensions. , 2010, Physical review letters.

[16]  J. Rothstein,et al.  Extensional rheology of a shear-thickening cornstarch and water suspension , 2010 .

[17]  Robert D Deegan,et al.  Stress hysteresis as the cause of persistent holes in particulate suspensions. , 2010, Physical review. E, Statistical, nonlinear, and soft matter physics.

[18]  Eric Brown,et al.  Generality of shear thickening in dense suspensions. , 2009, Nature materials.

[19]  É. Clément,et al.  Inclined plane rheometry of a dense granular suspension , 2010 .