Experimental investigation of a freely falling liquid drop in air*

The dynamics of a freely falling liquid drop in air was examined experimentally using a high speed camera. To obtain the freely falling drop we placed a drop on a plate and propelled the drop by using a pneumatic cylinder arrangement. This drop then reaches a terminal height before it starts to freely fall and then the drop dynamics are recorded. We investigate how the drop deforms initially and during free fall as a function of the drop velocity, size of droplet and liquid properties such as viscosity. In addition, the influence of the surface such as hydrophobic surface is an important parameter for initial drop contact angle. This work was motivated to experimentally validate the dynamics of a non-spherical liquid droplet falling in air which had been presented using simulations by Agrawal et al. [1].

[1] M. Agrawal, A. R. Premlata, M. K. Tripathi, B. Karri and K. C. Sahu, “Nonspherical liquid droplet falling in air”, PHYSICAL REVIEW E., 2017, 95,033111