Micrometric granular ripple patterns in a capillary tube.
The oscillatory motion of a fluid carrying micron-sized particles inside a capillary tube is investigated experimentally. It is found that initially uniformly distributed particles can segregate and accumulate to form regularly spaced micron-sized particle clusters. The wavelength of the microclusters is compared to data for macroscale sand-ripple patterns and found to obey the same universal scaling as these. A dimensional analysis is performed that confirms the universality of the experimentally observed scaling. The experimental data for the microripple clusters further suggest the existence of a minimum particle length scale for which patterns can form and below which the Brownian motion associated with the molecules of the matrix fluid inhibits pattern formation.
Zoueshtiagh
F
F
Laboratoire de Mécanique de Lille UMR CNRS 8107, Bd Paul Langevin, 59655 Villeneuve d'Ascq, France.
Thomas
P J
PJ
Thomy
V
V
Merlen
A
A