Abstract: This invention is directed to a nozzle configuration capable of enhancing the cutting and drilling effects of high pressure liquid fluid jets. The jet system is particularly adapted to configurations of two or more liquid jets which are oriented to converge at a common point. The internal nozzle configuration produces controlled instability in the jet stream causing a more rapid breakup into droplets which can be combined to produce very fast moving jets and slow moving jets when collision between droplets occur. The velocity of the fast jets so formed may be several times greater than the original velocity of the droplets upon emergence from the nozzle orifices. The interiors of the nozzles are formed with circumferential grooves or protrusions which produce perturbations in the jet streams causing rapid break-up into droplets.