Related Experiment Video
Updated: Aug 20, 2026

Film Control to Study Contributions of Waves to Droplet Impact Dynamics on Thin Flowing Liquid Films
Published on: August 18, 2018
Reflectivity-based evaluation of the coalescence of two condensing drops and shape evolution of the coalesced drop
Shripad J Gokhale1, Sunando DasGupta, Joel L Plawsky
1The Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Abstract:
Image analyzing interferometry is used to study the details of the evolving shapes and coalescence of two condensing drops of 2-propanol on a quartz surface. The measured thickness profiles give fundamental insights into the transport processes within the drops before and after coalescence and the evolution of the coalesced drop from asymmetric to symmetric shape. The results indicate that the constant value of the adsorbed film thickness between the drops and profiles of the local thickness, slope angle, curvature, and curvature gradient govern the pressure fields in the coalescing drops. The shape evolution after coalescence is found to be driven by the capillary forces within the drop. Using the experimental data, we find that the calculations of the average shear stress for the fluid flow between the drops, the decrease in the interfacial excess energy, and the positions of the center of mass of the drops explain the physics of the coalescence phenomenon. However, the flow field is found to be complex because the pressure field indicates that there are complicated flows within the drop.
Related Concept Videos
Precipitate Formation and Particle Size Control
The obtained precipitate should be either a pure substance of known composition or easily converted to one by a simple process, such as ignition or drying. In addition, the precipitate should be insoluble and easily filterable. In general, filterability...
Precipitation Processes
Colloidal precipitates
Types of Coprecipitation
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Washing, Drying, and Ignition of Precipitates
Recrystallization: Solid–Solution Equilibria

