CLUSTERS OF PARTICLES
FALLING IN A VISCOUS FLUID WITH PERIODIC BOUNDARY CONDITIONS
M. L. Ekiel-Jeżewska and B. U. Felderhof
Phys. Fluids 18, 121502 (2006)
Three identical point particles falling under gravity in a viscous
fluid with periodic boundary conditions. Stable (top) and unstable
(down) solutions of the equations of Stokesian dynamics are shown for
two initial configurations: horizontal equilateral triangles with side
lengths d=0.42 and d=0.43 close to a critical size d=0.4242. Four
periodic cubic
cells of unit length are visible in each window. The frame of reference
is moving with the time-averaged velocity of the red and blue
particles.
Transition from periodic to irregular motion,
caused
by an extremely small numerical perturbation
(d=0.43, front view).
See also: M. L. Ekiel-Jeżewska and B. U. Felderhof, Periodic
sedimentation of three particles in periodic boundary conditions,
Phys.
Fluids 17, 093102 (2005). PDF
