An experimental study of the stability of liquid bridges subject to shear-induced closed-flow

This paper shows via experiments, the effect of closed-flows on the stability of a liquid bridge. Experiments were conducted with a 3M™ HFE-7500 liquid as the liquid bridge and a mixture of sodium polytungstate solution and glycerine as the outer liquid, which is encapsulated in a cylindrical cavity. Depending on the glycerine content, the Bond number ranged from 0.04 to 0.25. It was shown that a closed-flow in both the encapsulating liquid and the bridge would increase the stability of a non-cylindrical bridge depending on the direction of shear, the Bond number and the bridge volume. It was also shown that, for a given bridge volume and Bond number, there is a capillary number that gives the maximum percentage stabilization. Any further increase in the capillary number flips the direction of the bulge from top to bottom or vice versa thereby decreasing the stabilization and at some capillary number even destabilizing the bridge. The scaling of the problem was analyzed through experimental data.

A series of pictures from an experiment. (a) The bridge is bulging from the bottom. (b) The wall is moved to induce shear. The interface is symmetric. (c) Wall is moved faster. The bulge flips direction.Figure optionsDownload high-quality image (41 K)Download as PowerPoint slide