DEVELOPMENT OF PHASED TWIN FLIP-FLOP JETS

The flip-flop nozzle is a device that can produce an oscillating jet f low without any moving parts. There is now a renewed interest in such nozzles due to their potential for use as excitation devices in practi cal applications. An experiment aimed at developing twin flip-flop jet s that operate at prescribed frequencies and phase differences was per formed. The phasing was achieved using two different nozzle interconne ction schemes. In one configuration the two jets flapped in-phase and in another they flapped out-of-phase with respect to each other. In ei ther configuration the frequencies of oscillation of both jets were eq ual. When one of the jets was run at a constant high velocity and the velocity of the second jet was increased gradually, the higher velocit y jet determined the frequency of oscillation of both jets. The two fl ip-flop jet configurations described in this paper could be used to ex cite a primary jet flow in either an anti-symmetric (sinuous) or a sym metric (varicose) mode.