Research on effectiveness enhancement of split drag rudder based on dual synthetic jets

To address the control dead zone in split drag rudder (SDR) of flying wing aircraft (FWA) at small deflection angles, a novel rudder effectiveness enhancement method based on dual synthetic jets (DSJs) is proposed. Dual synthetic jet actuators (DSJAs) positioned on the SDR inner surface can actively manipulate flow separation, enhancing drag coefficient by 33.73% when rudder deflection angle is equal to 10°. The control effectiveness emerging an increasing tendency with increasing deflection angle. Flow evolution indicates that the baseline SDR flow field exhibits incomplete separation, leading to an insufficient pressure differential across the SDR and low aerodynamic control efficiency. DSJs induce vortex development via momentum injection and suction effect, enhancing the pressure differential, thereby improving the SDR's aerodynamic performance. Cluster-based network modeling (CNM) of flow snapshots reveals that baseline modes concentrated in the wake evolve as a periodic Kármán vortex street, while controlled modes shift to the inner surface with dispersed energy distribution, exhibiting double-cycle oscillations.