Star-shaped Oscillations of Leidenfrost Drops

Abstract

We experimentally investigate the self-sustained, star-shaped oscillations of Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a heated, curved surface. We observe modes with $n=2-13$ lobes around the drop periphery. We find that the wavelength of the oscillations depends only on the capillary length of the liquid, and is independent of the drop radius and substrate temperature. However, the number of observed modes depends sensitively on the liquid viscosity. The dominant frequency of pressure variations in the vapor layer is approximately twice the drop oscillation frequency, consistent with a parametric forcing mechanism. Our results show that the star-shaped oscillations are driven by capillary waves of a characteristic wavelength beneath the drop, and that the waves are generated by a large shear stress at the liquid-vapor interface.

References in corpus (1)

• Maximum size of drops levitated by an air cushion

Cited by in corpus (12)

• Culinary fluid mechanics and other currents in food science
• Self-organized oscillations of Leidenfrost drops
• Asymptotic theory for a Leidenfrost drop on a liquid pool
• The Minimum Leidenfrost Temperature on Smooth Surfaces
• Structural diversity in electrohydrodynamically driven active and organized liquid states
• Harmonic and subharmonic waves on the surface of a vibrated liquid drop
• Sounds of Leidenfrost drops
• Complete modes of star-shaped oscillating drops
• Liquid Surfaces with Chaotic Capillary Waves Exhibit an Effective Surface Tension
• Small Leidenfrost droplet dynamics
• Model for self-organized Leidenfrost rotating polygons as cnoidal waves
• An alternate approach to simulate the dynamics of perturbed liquid drops