TY - JOUR
T1 - Velocity oscillations and stop-go cycles
T2 - The trajectory of an object settling in a cornstarch suspension
AU - von Kann, Stefan
AU - Snoeijer, Jacco H.
AU - van der Meer, Devaraj
PY - 2013
Y1 - 2013
N2 - We present results for objects settling in a cornstarch suspension. Two surprising phenomena can be found in concentrated suspensions. First, the settling object does not attain a terminal velocity but exhibits oscillations around a terminal velocity when traveling through the bulk of the liquid. Second, close to the bottom, the object comes to a full stop but then reaccelerates before coming to another stop. This cycle can be repeated up to 6 or 7 times before the object reaches the bottom to come to a final stop. For the bulk, we show that shear-thickening models are insufficient to account for the observed oscillations and that the history of the suspension needs to be taken into account. A hysteretic model, that goes beyond the traditional viscoelastic ones, describes the experiments quite well but still misses some details. The behavior at the bottom can be modeled with a minimal jamming model.
AB - We present results for objects settling in a cornstarch suspension. Two surprising phenomena can be found in concentrated suspensions. First, the settling object does not attain a terminal velocity but exhibits oscillations around a terminal velocity when traveling through the bulk of the liquid. Second, close to the bottom, the object comes to a full stop but then reaccelerates before coming to another stop. This cycle can be repeated up to 6 or 7 times before the object reaches the bottom to come to a final stop. For the bulk, we show that shear-thickening models are insufficient to account for the observed oscillations and that the history of the suspension needs to be taken into account. A hysteretic model, that goes beyond the traditional viscoelastic ones, describes the experiments quite well but still misses some details. The behavior at the bottom can be modeled with a minimal jamming model.
KW - METIS-296915
KW - IR-89944
U2 - 10.1103/PhysRevE.87.042301
DO - 10.1103/PhysRevE.87.042301
M3 - Article
SN - 1539-3755
VL - 84
JO - Physical review E: Statistical, nonlinear, and soft matter physics
JF - Physical review E: Statistical, nonlinear, and soft matter physics
IS - 042301
M1 - 042301
ER -