Fig. 4: Droplet ejection mechanism.
Coalescence of two H2 bubbles of unequal size, shown by snapshots from (a) an experiment and (b) a numerical simulation. In the experiment, both bubbles were produced during electrolysis in 0.5 mol L−1 H2SO4. While the bigger bubble is pinned to a blunt needle, the smaller bubble rises from the electrode until the coalescence begins at t0 = 0. The coalescence process is accompanied by the injection of two droplets after their consecutive separation from the jet. The first snapshot in (a) (not to scale) demonstrates the configuration, marking the region of interest with a red rectangle. The image recording was performed at 120 kHz. For further details, we refer to Supplementary Movie 7.
