THE INFLUENCE OF INTERFACE PROFILE ON THE ONSET OF LONG-WAVELENGTH MARANGONI CONVECTION

Recent experimental results [J. Fluid Mech. 345, 45 (1997)] for long-w avelength surface-tension-driven rupture of thin liquid layers (simila r to 0.01 cm) found the onset for significantly smaller imposed temper ature gradients than predicted by linear stability analyses that assum e an initially flat interface with periodic boundary conditions. The p resence of sidewalls and other aspects of the experiment, however, led to deformed interfaces even with no imposed temperature gradient. The se sidewall effects were not due to a small system size since experime nts with aspect ratios as large as 450 were significantly affected. Th e stability analysis presented here takes into account the effects of the deformed interface profile and shows that these effects account fo r some of the disagreement between experiment and theory. In addition, deviations from standard linear stability theory caused by these effe cts have the same qualitative behavior as the deviations seen in the e xperiments. (C) 1998 American Institute of Physics. [S1070-6631(98)016 12-2].