Influence of Internal Structural Parameters on the Inner Flow and Outer Spray Characteristics for Feedback-Free Fluidic Oscillator

Feedback-free fluidic oscillators, relying on the interaction of jets to oscillate, have a wide range of operation frequencies and no moving parts, which is promising for future applications. In this paper, the sweep angle, oscillation frequency, and volume flow rate of the feedback-free fluidic oscillator with a cavity width of 4.6 mm were measured experimentally, and the sweeping mechanism was analyzed based on the internal flow simulation. The influence of the impact angle, cavity exit width, and shoulder radius on the internal flow and external spray characteristics was analyzed by the numerical method. The results show that the sweep angle and oscillation frequency are affected throughout the increase in impact angle from 80° to 120°. However, only when the SR is greater than 0.88 mm does the internal flow and spray state change significantly. The volume flow rate is mainly affected by the cavity exit width and increases linearly from 5.3 mL/s to 9.3 mL/s as the width increases from 0.45 mm to 0.85 mm. It can be surmised that the sweep angle is approximately linear with the distance between the hit point and the impact cavity centerline.