Understanding the growth dynamics of capillary bridges

Description

We experimentally and numerically explore the dynamic growth of a capillary bridge formed when a solid sphere gently touches a thin film of silicone oil on a glass substrate.
Fluorescence microscopy measurements reveal the formation of a local minimum in the height profile near the oil-sphere contact. The dimple causes a large resistance to oil flow towards the forming bridge which slows down its formation considerably. The flow in the thin film is driven by a pressure gradient that is predicted by the momentary curvature of the liquid bridge. Using thin film lubrication theory, we calculate the height profile as a function of time. These profiles match, for a wide variety of initial film thicknesses,
sphere radii and substrate lengths with experimentally observed trends of the evolution of the capillary bridge and with the dimple profiles obtained from the fluorescence measurements. For an initial film thickness just below a characteristic thickness, the resistance is orders of magnitude higher than for an initial film thickness just above the characteristic thickness.

Period	20 May 2024
Event title	78th STLE Annual Meeting & Exhibition 2024
Event type	Conference
Location	Minneapolis, United States, MinnesotaShow on map