Controlling Fluidic Oscillator Oscillation Modes by Modifying Inlet Throat Width

This study numerically investigates the operating characteristics of a fluidic oscillator with a modified inlet throat width, expressed as [Formula: see text] (a ratio to the original width), to broaden its application range in flow separation control. Reducing the throat width destabilizes the main jet’s attachment in the mixing chamber. At [Formula: see text], two modes appear, randomly switching between high-frequency, low-amplitude (HF-LA) and low-frequency, high-amplitude oscillations. A further reduction to [Formula: see text] stabilizes the oscillation into the HF-LA mode but with a significant increase in total pressure loss. In contrast, a slight enlargement ([Formula: see text]) causes only minor behavioral changes. However, a large enlargement to [Formula: see text] shifts the oscillator to a low-frequency, low-amplitude mode. Here, the sweeping angle amplitude remains near 15 deg, and the total pressure loss is reduced by 40% compared to the baseline. Finally, the numerical simulation data in this study were compared with experimental data from the literature. The results show a high degree of agreement, demonstrating that adjusting the inlet throat width can effectively select different oscillation modes. If the inlet width could be made actively controllable in the future, it would significantly broaden the application potential of fluidic oscillators.