Figure 7
From: Directional Movement of Droplets in Grooves: Suspended or Immersed?

Generating droplets with desired sizes by a V-shaped structure.
A V-shaped structure is mounted on a stainless steel microsyringe needle and the volume of the departing droplet can be easily adjusted. The volume of the departing droplet is a function of the cross sectional angle, β and the distance between the needle tip and the groove bottom, h.