01. Experimental/Computational Fluid Dynamics

Fundamental studies have been conducted to control the direction of jet without changing the slot outlet geometry. Furthermore, the effects of the dimensionless frequency and momentum ratio of a synthetic jet on the deflection characteristics of a continuous jet, which is the primary flow, have been reported. Recently, continuous jet control using synthetic jets was expanded to include flip-flops, and the flow characteristics of the jet, including its unsteady characteristics, were clarified. However, in many previous studies on jet interference, the primary flow was a steady continuous jet, and the concept of phase did not exist between the primary and secondary flows. Limited studies on the relationship between jet interference and phase have been performed. To create a strong jet interaction and more actively control the primary flow, a pulsating jet and synthetic jet have been employed as the primary and secondary flows, respectively. This approach allowed for the effective control of the flow field by the phase of the velocity fluctuation. In this paper, we propose a method for controlling the flow field by adding an interference to the pulsating jet of the main flow using a synthetic jet. We attempted to experimentally elucidate the relationship between jet deflection characteristics and phase. The flow characteristics of the flow field generated by the jet interference were investigated by varying the phase for several dimensionless strokes under the conditions of equal time-averaged momentum of the pulsating jet and the synthetic jet. The results revealed that the jet direction could be precisely controlled by phasing the pulsating jet with a synthetic jet. Moreover, under conditions of large dimensionless stroke lengths, the intensity of discrete vortices generated by the roll-up of the velocity shear layer increases, and the phase effect on the vortex configuration of the vortices becomes more pronounced.