The Settling Velocity in Oscillating Water of Two Kinds of Particles Having the Same Settling Velocity in Stationary Water

Influence of Water Pulsation with Different Frequency and Amplitude on Orbit of a Particle Placed on a Fixed Screen

“…For example, the equal settling ratios of particles with different specific gravities falling in vertically oscillating water are not known. In previous reports [1][2][3] we have confirmed by experiments and calculations that the equal setting ratios in vertically oscillating water are smaller than that in stationary water.…”

Alteration of the equal settling ratio of fine particles by vertically-oscillating water

“…Although the reason for this originates in the complicated particle movement seen in actual separators, even the influence of simple periodic motion such as oscillation, which is utilized in many separators, on the equal settling ratio is almost never taken into consideration. In particular, the phenomenon of particle settling velocities being slowed in vertically oscillating water has been known for many years, but there are no reports investigating the equal settling ratio that take this phenomenon into consideration other than our previous report (Oki et al, 2005).…”

“…The equal settling ratio consequently was a maximum of about 13% smaller than that in stationary water. The calculation accuracy, as influenced by the solution conditions of the differential equation, equations of drag coefficient, and a Basset term were also investigated in that report (Oki et al, 2005). Although the lowering of settling velocity could be estimated by calculation, a slight difference between the above two samples in oscillating water could not be estimated with sufficient accuracy, except in regions of low oscillating acceleration.…”

“…In our previous report (Oki et al, 2005), we used glass (average 434.6 μm) and zirconia (average 202.4 μm) particles, which have the same settling velocity in stationary water, in a monodisperse system as samples. Their settling velocities in vertically oscillating water were measured and the equal settling ratios calculated.…”

“…Although the lowering of settling velocity could be estimated by calculation, a slight difference between the above two samples in oscillating water could not be estimated with sufficient accuracy, except in regions of low oscillating acceleration. In this study, based on our previous report (Oki et al, 2005), the influence of particle size on the change in the equal settling ratio in oscillating water seen at a low frequency of 10 Hz (maximum amplitude: 25.5 mm) was investigated using three kinds of sample pairs of glass (93 μm-435 μm on average) and zirconia (52 μm-202 μm on average) with the same settling velocity in stationary water.…”