We are conducting a slurry flow
experiment to produce behavior like in these photos (below) obtained
in Peko Hosoi's lab at MIT.
To the right is a picture of lab alumnus Chi Wey with the apparatus.
Glass beads of a uniform size are mixed into
a less dense viscous fluid. The
resulting slurry is poured into a reservoir at the top of an inclined
plane. A controlled amount of the slurry is allowed to flow through a gate
down the incline. At low inclination angles and concentrations,
the particles tend to settle out of the mixture and stick to the surface
of the incline, leaving a clear fluid to flow down the slope (left panel).
At intermediate angles and concentrations, a well-mixed slurry flows
down the slope (middle panel) producing the characteristic fingering
pattern seen in visous films. At high inclination angles and particle
concentrations (right panel) the beads tend to collect at the front
of the film; their presence drastically changes the dynamics of
the contact line, supressing fingering and producing a pronounced ridge.
For more discussion of this problem and other problems we work on,