Forward, reverse, and no motion of Marangoni surfers under confinement

Abstract

The propulsion characteristics of Marangoni surfers under confinement is examined. Through experimental measurements and numerical simulations, it is demonstrated that, contrary to what might be the usual expectation, the surfers may propel themselves in the direction of lower surface tension. It is discovered that negative pressure is the primary contributor to the fluid force experienced by the surfer and that this suction force is mainly responsible for the reverse Marangoni propulsion.