Droplet detachment and pinch-off of bidisperse particulate suspensions

Bifurcation from bubble to droplet behavior in inviscid pinch-off.

High-speed video is used to analyze the pinch-off of xenon in water. By varying the pressure in the xenon from 0.05 to 68 atm, the mass density ratio D=rho(int)/rho(ext) of the interior gaseous xenon rho(int} to the exterior liquid water rho(ext) can be varied by over 3 orders of magnitude. Both the shape of the pinch region and the power law that governs the collapse of the minimum neck radius...

Simulation and Modeling of Mono- and Bidisperse Suspensions

Autocatalytic plume pinch-off.

A localized source of buoyancy flux in a nonreactive fluid medium creates a plume. The flux can be provided by either heat, a compositional difference between the fluid comprising the plume and its surroundings, or a combination of both. For autocatalytic plumes produced by the iodate-arsenous acid reaction, however, buoyancy is produced along the entire reacting interface between the plume and...

Giant bubble pinch-off.

Self-similarity has been the paradigmatic picture for the pinch-off of a drop. Here we will show through high-speed imaging and boundary integral simulations that the inverse problem, the pinch-off of an air bubble in water, is not self-similar in a strict sense: A disk is quickly pulled through a water surface, leading to a giant, cylindrical void which after collapse creates an upward and a d...

The Structure of Bidisperse Suspensions at Low Reynolds Numbers

We present a simulation technique for the direct simulation of the motion of spherical particles suspended in fluids at low Reynods numbers. We use this method to simulate bidisperse suspensions at varying size ratios of the suspended spheres and compare to analytic results of Batchelor for the low concentration regime. We find that the pair correlation functions indicate that three body hydrod...