(203e) Cascading granular flow in a quasi-two-dimensional rotating drum

Studies of granular
surface flow in a rotating drum are of importance in both scientific and
industrial field. However, little work has been found for high rotational speed
drum in the literature, which has a wide uses, such as pharmaceutical, food, chemical and ceramic
industries.
In this paper, the granular flow in cascading regime is studied via particle
image velocimetry (PIV) system in a quasi-two-dimensional rotating drum.

At
high rotational speeds, the free surface profile no longer stays flat, and
becomes increasingly S shaped with increase of Froude number (Fr=ω²R/g, where ω is the angular speed, R is the drum
radius, and g the gravity acceleration). Particles can be divided into three
regions, active, passive and particle raining regions. The influences of
operational variables such as rotating speed and size ratio are discussed.
Finally, simple equations are derived to describe the granular dynamics using
the thin layer approximation theory.