Abstract:
We study experimentally the effect on liquid film flow of two apparently innocuous geometric constraints, a finite channel width and a periodically corrugated bottom wall. Results for flat channels with side-walls show large deviations from 2-D predictions, both in the primary instability and in the post-threshold traveling waves. Deviations scale with the Kapitza number (capillary to viscous stresses), and indicate operation of an inherently 3-D wave attenuation mechanism that provides long-range transverse coherence to the flow. Substituting the flat wall with a periodically corrugated one modifies fundamentally the primary instability. The classical, long-wave mode is significantly postponed, and at intermediate-large inclinations is preceded by a short wave mode that initially has the wavelength of the wall. Energy transfer between the modes provides a tentative explanation for the observations.
ADDITIONAL INFORMATION:
The research interests of Vasilis Bontozoglou include experimental and computational transport phenomena, multiphase flows, theoretical and computational fluid mechanics, as well as analysis and design of process equipment for chemical engineering.
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