Aero- and hydroacoustics of the impact for a droplet freely falling onto the water surface

Aero and hydroacoustics of the impact for a droplet freely falling onto the water surface was studied. The experiments were conducted in a basin of size of 2.5 × 0.6 × 0.45 m3 filled with degassed tap water at room temperature. Regular droplet series and individual droplets were formed with the help of a dosing profiled nozzle device with an output diameter of 0.4 cm. The altitude Hd of the droplet fall varied within the range of 8 to 110 cm. The size of droplets and of caverns produced by the droplets was determined. The disturbance of the water surface was detected by an optical (laser) system adapted to measuring the surface waves. The output signals from optical and acoustic receivers were applied to the inputs of a specified interface, and then were digitized. All these results testify to the fact that the sound generation mechanism is localized on the free surface and is general for acoustic signals propagating through both media.