The latter can be regarded as the version for our fluid configuration of the classical flow-focusing formula [59].
It can be readily derived if one neglects both energy dissipation in the gas meniscus [Fig. 9(b)] and the gas kinetic energy at the feeding capillary end and assumes that both the pinch location and the proportion between the precursor jet and resulting bubble diameters do not significantly depend on Qg/Ql .
Quasimonodisperse collections of microbubbles were produced, as indicated by the very lowstandard deviations of the bubble diameter histograms obtained from the experiments [Fig. 14(b)].