Event № 1035
Rayleigh-Taylor instability (RTI) occurs at the interface between two fluids of different densities, when the heavier fluid is accelerated toward the lighter one. This instability is ubiquitous in many natural, as well as industrial settings, and may occur over a wide range of scales ranging from supernova explosions, to cloud settling and liquid film coatings. In various engineering applications, it is important to control, and often suppress RTI. Recently, it was demonstrated that RTI can be harnessed to shape liquid polymer films into drop-shaped structures, which can then be cured to produce smooth elastic materials with drop-like topography, illustrating the need for deeper understanding of the evolution and possible control of the RTI in suspended liquid films, as a means for advanced fabrication capabilities.
Here, we present a model for shaping thin liquid films in the Rayleigh-Taylor configuration by controlling the pressure at the surface of the substrate from which the liquid is suspended. Using long-wave approximation we derive an ordinary differential equation governing the steady-state position of the liquid film obtained from the balance between gravitational and capillary forces. We pose and solve the inverse problem which allows to find the required pressure distribution at the solid-liquid interface for a given steady-state position of the liquid-gas interface. These results may be applied for fabrication of smooth solidified elastic surfaces out of liquid films with deliberate complex topographies.
Joint work with Ranga Narayanan and Alexander Oron