The role of geometry on controlled cavity collapse and top jet drop

Abstract

The contents of this work explore the influence of three geometric parameters on controlled cavity collapse at liquid interface and the subsequent ejected drop; the parameters are the angle of the ejecting nozzle plate (θ), the height (H), and the radius (R) of the vessel used to enclose the liquid within. The conducted computational modeling shows that changing the angle of the nozzle plate from a flat surface to inclined surface in one direction causes the droplet diameter to decrease, whereas an inclination in the opposite direction results in larger droplets. Moreover, changing the height of the fluid vessel does not actually influence the drop size and its velocity as long as the vessel height is much larger than the nozzle radius (R0). Below the limit H = 5R0, the droplet size starts to decrease and its velocity to increase by decreasing the vessel height. Finally, the droplet size decreases by increasing the radius of the fluid vessel even when R ≫ R0. This is attributed to the change in the displaced liquid volume and subsequently the cavity volume at the tip of the nozzle when the vessel radius is changed.