Deformation of liquid drops moving in a gas medium

Deformation of drops (with initial characteristic sizes of 3–6 mm) of widely used liquids (water, kerosene, and ethyl alcohol) moving in air with moderate velocities (up to 5 m/s) is investigated experimentally using a high-speed (10$^5$ frames per second) video camera. The characteristic “deformation cycles” for drops are established. The duration, length, and amplitude of variation of the drop sizes in each cycle are determined. It is shown how the initial size and velocity of drops affect these characteristics. The experimental results are processed using the similarity criteria (Weber and Reynolds numbers) adopted for investigating the motion of liquid drops. The features of the processes under investigation are outlined; it is shown that the conditions and characteristics of deformation of drops are determined not only by the effect of viscous, inertial, and surface tension forces.