A standing Leidenfrost drop with Sufi-whirling

TL;DR

This paper reports a novel standing Leidenfrost state where a drop partially adheres to a heated surface and self-rotates like Sufi-whirling, revealing new insights into drop-surface interactions and dynamics.

Contribution

It introduces the discovery of a standing Leidenfrost state with partial adhesion and self-rotation, expanding understanding of drop behavior on heated surfaces.

Findings

Drop exhibits stable partial adhesion with thermal and mechanical equilibrium.

Drop self-rotates in a Sufi-whirling manner due to partial adhesion.

Imaging reveals evolution of adhesion, circulation, and rotation.

Abstract

The mobility of Leidenfrost drop has been exploited for the manipulation of drop motions. In the classical model, the Leidenfrost drop was levitated by a vapor cushion, in the absence of touch to the surface. Here we report a standing Leidenfrost state on a heated hydrophobic surface where drop stands on the surface with partial adhesion and further self-rotates like Sufi-whirling. To elucidate this new phenomenon, we imaged the evolution of the partial adhesion, the inner circulation, and the ellipsoidal rotation of the drop. The stable partial adhesion is accompanied by thermal and mechanical equilibrium, and further drives the development of the drop rotation.