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Capillary surfers and spinners on a vibrating liquid bath
Capillary surfers are wave-driven particles at a fluid interface that have been recently introduced by Ho et al. (arXiv:2102.11694v3, 2023) and described theoretically by Oza et al. (arXiv:2301.05767, 2023). A surfer is a hydrophobic, millimetric solid particle, the bottom surface of which is pinned to the air-water interface of a vertically vibrating bath. The relative vertical motion of the particle and the interface leads to the generation of propagating capillary waves. When the mass of the particle is unevenly distributed, the particle generates an asymmetric wave field and self-propels along the interface with constant speed on a straight line.
I will describe the behavior of capillary surfers and introduce capillary spinners, chiral particles that rotate on the surface of a vibrating bath (Barotta et al. arXiv:2211.07495v2, 2022). The speed and interaction of both these types of particles with their environment can be tuned broadly through the particle, fluid, and vibration parameters. These particles interact with one another through their mutual capillary wavefield and exhibit a set of collective modes characterized by a discrete number of equilibrium spacings for a given set of experimental parameters.