Regensburg 2016 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 14: Complex Systems
DY 14.6: Vortrag
Montag, 7. März 2016, 17:30–17:45, H47
A novel experimental technique for analyzing spreading droplets — •Roghayeh Shiri1, Ali Najafi1, and Mehdi Habibi2 — 1University of Zanjan, Zanjan, Iran — 2Institute for advanced studies in basic sciences, Zanjan, Iran
Recently, a simple and accurate phase measurement method, called the sampling moiré method was developed for thickness distribution measurement of transparent plates from a single image. A single image taken from a Ronchi grating that encoded the optical characteristics of transparent sample is the main experimental element of the sampling moiré method. This method can obtain small displacements up to 1/500 of the grating pitch by analyzing the phase distribution of the moiré fringe of each single grating image before and after deformation.
Therefore, Sampling moiré method can provide an accurate technique to investigate the dynamical properties of a spreading droplet of a transparent fluid over a rigid substrate where the air-liquid interface evolves in time. Studying the dynamics of such a multi-phase flow interface is interesting either from fundamental or technical point of view.
We have performed the spreading experiment with silicone oils with different viscosities and compared them with a universal scaling relation that quantifies the early time dynamics in non-gravitational regime as:h(t)∼ t−0.2. In our experiments, all droplets with different viscosities show a linear dynamics with slope −0.2 in the logarithmic scale that are in good agreement with the theoretical results.