双后掠鸭翼气动特性的数值模拟

首先针对具有中等前缘后掠角梯形鸭翼的缺点提出双后掠鸭翼概念，然后分别对安装梯形鸭翼和双后掠鸭翼的近距耦合鸭式布局的气动性能进行数值模拟研究，分析影响双后掠鸭翼气动性能的流动机理。研究表明：在大迎角时，对于双后掠鸭翼，具有较大前缘后掠角的外翼段可以使鸭翼涡在涡核破裂后仍能形成稳定集中涡并保持较高的强度，增加鸭翼本身的失速迎角，并通过诱导作用改善机翼外翼段流场，进而提高全机大迎角性能，但在小迎角时会破坏鸭翼附着流或前缘气泡涡的发展，造成略微的升力损失。拥有较大失速迎角的双后掠鸭翼在小迎角时具有较大的可用偏度，可以增强布局的抬头控制能力。双后掠鸭翼在满足隐身约束的前提下，超声速阻力较小，具有较好的超声速性能。

Numerical Simulation on the Aerodynamic Performance of the Double Swept Canard

The concept of a double swept canard is proposed in the first part of this paper for comparison with the poor performance of the trapezoidal canard with a moderate leading edge sweep angle. The aerodynamic performance of the canard configuration with the trapezoidal canard and the double swept canard is investigated respectively by numerical simulation, and the flow mechanism that affects the aerodynamic performance of the double swept canard is analyzed. The results show that, for the double swept canard, the outboard wing section with its large leading edge sweep angle can keep the canard vortex stable with high intensity after the vortex core breakdown, increase the stall angle of the canard, and improve the outboard wing flow field by induction. Thus,it can improve the aerodynamic performance of the configuration at high angles of attack, so that better aerodynamic performance of the configuration can be achieved. However, it suffers a slight lift loss at low angles of attack due to its adverse effect on the development of the attached flow and leading edge vortex. A double swept canard has larger deflection angles available at low angles of attack because of its larger stall angle, so that higher pitch up control capability can be achieved. On the premise of satisfying the constraints of stealth, a double swept canard has better supersonic performance because of its lower supersonic drag.