关键词: 小展弦比飞翼, 大迎角, 侧滑, 风洞试验, 数值模拟, 航向稳定性

Abstract: The low-aspect-ratio flying-wing configuration is a crucial development direction for future aircraft. To further illustrate the aerodynamic characteristics of such configurations at high angles of attack, a comprehensive analysis of the lat-eral and directional aerodynamic forces and moments of a low-aspect-ratio flying-wing model at high angles of attack was conducted by integrating wind tunnel force measurement tests, flow visualization tests, and numerical simulations. The results indicate that the lateral and directional aerodynamic characteristics of the model change drastically with increasing angle of attack under sideslip conditions. The directional static stability of the aircraft sharply decreases when the angle of attack exceeds 24°, and reaches an extreme value near 40° angle of attack. Moreover, as the angle of attack increases to 50°, the directional static stability returns to the level observed at low and moderate angles of attack. Flow field analysis reveals that sideslip accelerates the leading-edge vortex breakdown on the windward side while delaying the vortex breakdown on the leeward side. This results in a significantly asymmetric distribution of the low-pressure area on the nose, thereby producing strong destabilizing lateral force and yawing moment. Moving the cockpit rearward can reduce the vertical projection of the sideslip-induced asymmetric low-pressure area on the nose. This weakens the destabilizing lateral force in the nose region and can effectively mitigates the abrupt degradation of directional stability at high angles of attack.

Key words: low-aspect-ratio flying-wing, high angle of attack, sideslip, wind tunnel test, numerical simulation, directional static stability