Effect of Gurney flaps on aerodynamic characteristics of a spinning missile

The spinning missiles usually adopt oblique tails to generate the rolling moment. However, such a configuration suffers from the problem of poor stability of rotating speed, which affects the hitting accuracy. To improve the aerodynamic performance of spinning missiles, the traditional oblique tails are substituted with Gurney flaps on the trailing edge of the tails to generate rolling moment in the present study. Effect of the Gurney flap height on the aerodynamic characteristics of the missile is studied by performing numerical simulations, and also compared with the oblique tail model. The results show that the Gurney flaps can generate the rolling moment for the missile, which increases with the Gurney flap height. Compared to the oblique tail model, the Gurney flaps can provide a larger rolling moment for the missile with a relatively small impact on side force. The maneuvering efficiency of the Gurney flaps is slightly different at different Mach numbers. The rolling moment decreases with the increase of the angle of attack in the subsonic regime, while it remains nearly unchanged with the angle of attack variation in the supersonic regime. Meanwhile, the maneuvering efficiency of the Gurney flaps is lower in the supersonic regime compared to that in the subsonic regime. It is found that, the Gurney flaps induce asymmetric flow near the trailing edge of the missile tail, resulting in the occurrence of asymmetric pressure difference among the tails, thus leading to the rolling moment generation.