Characteristics of Ambivalent Flows in Diamond-Shaped Cylinder Bundles With Slit Flow

A new nozzle using a composite flow network has been developed for plain air film stabilization without film break. The design consists of a slit duct with layers of diamond-shaped cylinder bundles. Tests were conducted using air at average velocity of 8m/s. The new nozzle had a stabilized length in its flow direction stretching 2 times, compared to a conventional slit design. The development of new nozzle was based on fluid dynamic theory. A new type of intersecting flow networks, to be referred to as composite flow network, was constructed consisting of ambivalent flows superposed with con-current thin-film flows in diamond-shaped cylinder bundles. Our previous experiments have revealed the occurrence of flip-flop flow with self-sustained flow oscillations and the generation of longitudinal vortices in the diamond-shaped cylinder bundle. It is conceivable to extend longitudinal vortex flow in composite flow networks through interacting with flip-flop flow exiting from a pre-fixed multiple-intersecting flow network in order to strengthen and thus stretch its efflux.