Spreading of a constant volume of fluid down a vertical plane: Experiments and modelling

A. G. GONZÁLEZ, J. DIEZ, J. M. GOMBA, R. GRATTON, L. KONDIC

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

American Physical Society

Año: 2004 vol. 70 p. 263091 - 2630918

1063-651X

We study the thin film flow of a constant volume of silicon oil (PDMS)spreading down a vertical glass plate. The initial condition isgenerated from a horizontal filament of typical diameter $0.4~mm$. Twooptical diagnostic methods are used: one based on an anamorphic system,and the other on the schlieren method. The first one allows for adetailed  characterization of the early stable stage of the spreadingwhich is used to estimate the thickness of the precursor film needed tomodel the flow. The second one captures  the bidimensional pattern ofthe instability of the contact line. We use these techniques todetermine the micrometric  thickness profiles, the evolution of themoving contact lines, and the  shape and Fourier spectra of thefrontline. The numerical simulations for the stable  stage are in goodagreement with the experimental results. We develop a model based onlinear perturbations analysis that predicts the evolution of the modespresent in the linear stage of the instability.