Characteristics of Supersonic Sweeping Jet with Geometry Variation of Actuator Exits

Abstract

Supersonic sweeping jets (SWJs) have demonstrated their effectiveness across a variety of scenarios, particularly in aeronautic applications (e.g., lift enhancement). An experimental study is conducted to investigate the characteristics of SWJs emitted from actuators with different spreading angle [Formula: see text] and exit length [Formula: see text]. Schlieren visualization is used to capture the near- and far-field SWJs at nozzle pressure ratios (NPRs) ranging from 1.6 to 6.9. The results show that as NPR increases the SWJs become underexpanded when [Formula: see text]. Different [Formula: see text] have an impact on the shock structure and the law of the spreading angle of jet control area [Formula: see text] changing with NPR. When [Formula: see text] is approximately 100 deg, [Formula: see text] increases at first and then decreases with increasing NPR, reaching up to 90 deg at high NPRs. When [Formula: see text] is about 50 deg, [Formula: see text] remains roughly constant and equal to [Formula: see text]. Internal flow measurements reveal that flow attachment caused by the Coanda effect plays a significant role in the mechanism that leads to a change in [Formula: see text]. Proper orthogonal decomposition is applied to analyze the spatial and temporal patterns. Far-field measurements show multiple sound waves propagating upstream and downstream, which generated by the supersonic SWJs.