Transfer of the Substance of a Colored Drop in a Liquid Layer with Travelling Plane Gravity-Capillary Waves

The evolution of the distribution pattern of an ink droplet freely falling on the wavy surface of a liquid is traced by video-recording methods. A system of travelling plane gravity-capillary waves with a frequency of 5.0 < f < 50 Hz (a wavelength of 0.7 < lambda < 6.6 cm) was created by a vertically oscillating pointed strip. Drops of alizarin ink with diameter D = 0.5 cm fell freely from the dispenser and reached contact velocity U = 370 cm/s in the mode of splash formation. In the phase of primary contact and coalescence, the colored drop spreads in agitated liquid like in a quiet medium with the formation of a cavity with its bottom covered by colored fibers, a crown, and a splash. The growing crown is surrounded by a group of thin radial trickles with vortex heads and separate spots (wakes of earlier returned ejected droplets). Subsequently, the colored liquid on the surface is divided into three independently moving formations: a finely structured area of primary contact of an irregular shape, a submerging vortex ring, and a near-surface vortex dipole. In all components of the flow, the dye is distributed in the form of thin fibers for a long time until the final phase of erosion by residual flows and molecular diffusion processes. The geometry of movement and the general structure of the separated colored areas are traced.