A Basic Study of Self-Induced-Oscillation Jet Nozzle

Abstract

The authors experimentally investigate the oscillation frequency of a flip-flop jet nozzle. The trace of pressure difference between both the ends of a connecting tube is simply modeled by a triangular wave, and the velocity in the connecting tube is calculated by the Runge-Kutta method. A jet is assumed to switch when the integral JM, JK or JP reaches a threshold value, where JM, JK and JP are the accumulations of momentum, kinetic energy and mass which are transported through the connecting tube from a side wall with higher pressure into another side wall with lower pressure, respectively. As a result, JP is the most adequate among the three. Strouhal number calculated on the basis of JP agrees well with experimental one.