Related Experiment Video
Updated: Mar 31, 2026

Studying Surfactant Effects on Hydrate Crystallization at Oil-Water Interfaces Using a Low-Cost Integrated Modular Peltier Device
Published on: March 18, 2020
Hydrodynamics of Particles at an Oil-Water Interface
Archit Dani1, Geoff Keiser2, Mohsen Yeganeh2
1The Benjamin Levich Institute for PhysicoChemical Hydrodynamics and Department of Chemical Engineering, The City College of New York , 140 Convent Avenue, New York, NY 10031, United States.
Abstract:
This study is a theoretical and experimental investigation of the hydrodynamics of the mutual approach of two floating spherical particles moving along an oil-water interface. An analytical expression is obtained for the (inertialess) Stokes drag for an isolated particle translating on a flat interface as a function of the immersion depth into the water phase for the case in which the viscosity of the oil is much larger than that of the water. An approximation for the viscous drag due to the mutual approach of identical spheres is formulated as the product of the isolated drag multiplied by the resistance of approaching spheres in an infinite medium. Experiments are undertaken on the capillary attraction of large, millimeter-sized Teflon spheres floating at the interface between a very viscous oil and water. With the use of image visualization and particle tracking, the separation distance as a function of time [[Formula: see text](t)] is measured along with the immersion depth and predicted by setting the capillary attraction force equal to the viscous drag resistance. The excellent agreement validates the approximating formula.
Related Concept Videos
Surface Tension of Fluid
Surface tension varies...
Entropy and Solvation
Fluid Pressure over Flat Plate of Variable Width
The pressure distribution on the plate can be calculated by determining the force that acts on a differential area strip of the plate. Thus, the magnitude of the force is equal to the...
Steady, Laminar Flow Between Parallel Plates
Colloids
Viscosity of Fluid

