Oscillatory instability in the liquid layer with a deformable free surface

Abstract

We consider the classical problem of instability of the inhomogeneously heated liquid layer with the free surface in order to clarify the mechanism of convective instability for a novel oscillatory mode that was revealed recently. This mode exists when the thermocapillary effect and the gravity are absent; it is associated with the deformability of the free surface and with the thermal expansion of the fluid. The asymptotic short-wave analysis is performed for the inviscid fluid layer. Comparison of our analytical results with the previous numerical results allows us to propose the mechanism of a novel oscillatory instability. The Direct stability analysis… Проведено также прямое численное моделирование течений при неоднородном нагреве слоя жидкости в условиях невесомости и отсутствие термокапиллярного эффекта. The results for velocity filed and for the free surface deformation confirm the oscillatory instability of the liquid layer. Thus, it is concluded that the novel instability mechanism is that the liquid particle moved by the capillary wave arrives at the hotter spot on the deformable free surface, where it expand and enforced motion.