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Abstract: Capillary jetting of a fluid dispersed into another immiscible phase isusually limited by a critical Capillary number, a function of the Reynoldsnumber and the fluid properties ratios. Critical conditions are set when theminimum spreading velocity of small perturbations $v^* -$ along the jetmarginal stability velocity is zero. Here we identify and describeparametrical regions of high technological relevance, where $v^* - > 0$ and thejet flow is always supercritical independently of the dispersed liquid flowrate: within these relatively broad regions, the jet does not undergo the usualdripping-jetting transition, so that either the jet can be made arbitrarilythin yielding droplets of any imaginably small size, or the issued flow ratecan be made arbitrarily small. In this work, we provide illustrative analyticalstudies of asymptotic cases for both negligible and dominant inertia forces. Inthis latter case, requiring a non-zero jet surface velocity, axisymmetricperturbation waves ``surf- downstream for all given wave numbers while theliquid bulk can remain static. In the former case implying small Reynoldsflow we found that the jet profile small slope is limited by a critical value;different published experiments support our predictions.

Author: Alfonso M. Ganan-Calvo

Source: https://arxiv.org/

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