Forces acting on a particle: FA the added mass force, FD the drag force, FL the lift force, FG the gravity force or body force, FI the force due to acceleration of the flow, and FW the wall repulsive force.
Experimental setup. 1. Laser, 2. Drum, 3. Drum controller, 4. Camera, 5. Camera controller.
Solid-body rotational flow at a drum frequency of 0.60 Hz. (a) A snapshot of the PIV tracer particles. (b) Flow field inside the rotating drum. The scratched region is highlighted in gray color. The red line shows the position of the velocities shown in (c). (c) Velocity vs. position along a horizontal line shown in (b). The markers (red online) show the measured velocities and the black line is the theoretical velocity of solid body rotating flow.
Four regimes of a heavy particle trajectory: (1) Fixed-point regime, (2) cascading regime, (3) fixed solid body rotation regime, and (4) suspension regime.
Particle position of a 7 mm polystyrene particle in a drum for frequency 0.07–0.11 Hz. The cross markers show the average positions for each trajectory.
Images of a particle slightly heavier than the fluid with black and white texture in a drum. (a) Snapshots of a particle in orbital motion. (b) Zoomed image for a particle close to the wall.
The equilibrium radius vector re , the momentary position of the sphere r , and the particle velocity u . The particle turns around re with momentary angular velocity Ωp . The dashed black line represents the particle circular orbit. The cross marker shows the equilibrium point.
Comparison between experimental results and numerical solution from Eq. ( 5 ) for (a) radial center position and (b) radius of orbital motions as a function of Reynolds number (correspond to the drum frequency 0.07–0.11 Hz).
Paths reproduced by Eq. (5) for the drum frequency 0.07–0.11 Hz.
Magnitude of the particle velocity vs time normalized by the drum time cycle.
The absolute angular rotation of the sphere in a solid body rotating flow with f d = 0.07 Hz for one period of the drum.
The result of the flow field around a 7 mm particle in a drum at f d = 0.07 Hz using particle image velocimetry. (a) Flow field and (b) Velocities vs. positions along the lines shown in the left panel.
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