Elastic nozzles produce more robust jets*

Nozzle characteristics modulate the stability of liquid jets, but their role in jet robustness to external disturbances is understudied. Here we produce jets with thin elastic membranes containing a hole of approximately 500 μm in undeformed diameter. Our softest membranes produce the most stable jets in the Rayleigh and first wind-induced breakup regimes. An externally applied upstream pressure pulse lasting approximately 1 ms momentarily reduces the jet breakup distance and morphology. Softer nozzles and higher jet velocities minimize the disruption to the otherwise steady jet. Linear temporal theory for short nozzles, and derived using a dilated nozzle diameter, well predicts breakup length before and after the pressure pulse. We propose a hypothetical flow-rate and associated dilation for which our pressure impulse has no effect on jet stability. Pressure disturbances initiate morphological changes in the jet, introducing novel phenomena like jet thinning and exit coalescence. Our results demonstrate that nozzle compliance can play significant role in damping undesirable disturbances.