Scalar transport and nucleation in quasi-two-dimensional starting jets and puffs

We experimentally investigate the early-stage scalar mixing and transport with solvent exchange in a quasi-two-dimensional (quasi-2D) jet. inject an ethanol/oil mixture upward into quiescent water, forming quasi-2D turbulent buoyant jets triggering ouzo effect initial Reynolds numbers, Re0=420, 840, 1680. study two different modes of fluid supply: continuous injection to starting jet finite volume puff. While both start stage, puff exhibits characteristics transport, entrainment, mixing, nucleation, due lack supply. also dyed ethanol solution as passive reference case, such that nucleation for can be disentangled. For jets, total nucleated mass from seems very similar mass, indicating primary site slightly above virtual origin needle, supplying flux like injection. With site, mildly increasing rate suggests occurrence secondary throughout entire puffs, we show smallest Re0 propagates fastest its entrainment lasts longest. attribute superior performance buoyancy effect, which transforms thermal, has been proven have stronger entrainment. Although reduce drastically when stops, mild still leads non-zero rates reduced decay mean concentrations mixture. Adapting theoretical framework established Landel et al. (2012b) successfully model horizontally-integrated scalar. The fitted advection dispersion coefficients are then used mixture, spatial–temporal evolution extracted. spatial distribution sheds new light on process transient flows.