Aerodynamic characteristics of Gurney flaps under special atmosphere

The low Reynolds number and transonic Mach regime posed severe challenges to near space vehicle and Mars exploration aircraft. The configuration with lift enhancement device known as Gurney flap (GF) was focused on, and the aerodynamic characteristics of GF under special environment was predicted based on CFD method. Aerodynamic characteristics of the Eppler387 airfoil with GF was analyzed for different Reynolds numbers, Mach numbers, and GF heights. The results indicated that the circulation of airfoil was increased significantly as well as the lift of airfoil, because the leading sucking peak and trailing edge pressure difference between upper and lower surface were enlarged. Under higher Mach number, lower pressure region on the upper surface of airfoil was expanded, and position of shock wave was slightly delayed. The maximum lift-to-drag ratio of the airfoil was improved by GF with appropriate height, and the lift-to-drag ratio was increased obviously under high lift status. The study can provide technical support to the design and improvement of the near space vehicle and Mars exploration aircraft.