β Scribed by D. K. Vohra; Stanley Hartland
No coin nor oath required. For personal study only.
In a close packed dispersion, a drop at the interface experiences forces from the drops above which affect its shape and rate of coalescence. The shape of a vertical column of two drops approaching either a horizontal plane or deformable fluidβliquid interface is considered here. The surface of the upper drop is sessile and that of the lower drop is defined by the differential equations governing the shape of an annular meniscus with apex. These have been integrated on a digital computer and the areas of the draining films between the two drops and between the lower drop and the interface obtained. The forces pressing on the films may also be obtained when the drop volumes are known and hence the ratio of the coalescence times of the upper and lower draining films. For equisized drops, the results indicate that the lower drop always coalesces with the upper drop before it coalesces with the bulk interface. When the lower drop approaches a deformable interface, the areas of the draining films are almost identical with those associated with a single drop to which the same vertical force is applied through a horizontal surface. Solutions for this case are already available and hence provide an estimate of the areas of the draining films associated with the bottom drop in a vertical column containing several drops.
π SIMILAR VOLUMES