Shreyas Mandre

Associate Professor
Mathematics Institute, University of Warwick

Capillary interactions between nearby interfacial objects Europhys. Lett. 102, 38001 (2013) PDF

by He, Nguyen and Mandre
Fluid Mechanics Capillary Cheerios Effect


We develop a general method to study the capillary interactions between objects of arbitrary shape which float close to each other on an interface, a regime in which multipole expansion is not useful. The force is represented as a power series in the small distance between the objects, of which the leading order is finite. For objects with size a much larger than the capillary length lc, the force scales as (a/lc)1/2 and the prefactor depends on the mean radius of curvature R at the closest points. After contact the objects roll and/or slide with respect to each other to locally maximize R and therefore the force. For smaller objects (a < < lc), the force scales as (a/lc)-1/log(a/lc)2, and the prefactor depends only weakly on the shape and relative orientation of the objects.