Clouds of particles in a periodic shear flow

Bloen Metzger (1) , Jason E Butler (2)

1 IUSTI - Institut universitaire des systèmes thermiques industriels
2 UF|CHE - Department of Chemical Engineering [Gainesville]

We have investigated the time evolution of a cloud of non-Brownian particles sub- jected to a periodic shear flow in an otherwise pure liquid at low Reynolds number. This experiment illustrates the irreversible nature of particulate systems submitted to a shear. When repeating the cycles of shear, we have found that clouds of particles progressively disperse in the flow direction until reaching a threshold critical volume fraction that depends upon the strain amplitude; this critical volume fraction coin- cides with measurements of the threshold for reversibility found from experiments on homogeneous suspensions in periodic shear. Two distinct patterns, including a “galaxy-like” shape, are observed for the evolution of the clouds and the transi- tion between the patterns is identified using a simple scaling analysis. Movies are available with the online version of the paper.

Domaines: Mécanique des fluides [physics.class-ph]

Bloen Metzger, Jason E Butler. Clouds of particles in a periodic shear flow. Physics of Fluids, 2012, 24, pp.021703. ⟨10.1063/1.3685537⟩. ⟨hal-01442077⟩