The geometric effects of Coanda trailing edges on the aerodynamic performance of an airfoil are numerically evaluated for a range of different freestream Mach numbers and momentum coefficients. A Circulation control (CC) airfoil with a circular trailing edge (ACTE) proves to have better control effectiveness at low subsonic freestream speeds (Mach = 0.1). A CC airfoil having an elliptic trailing edge (AETE) outperforms the ACTE at high subsonic flow conditions. The occurrence of C_μ-stall for the AETE is greatly postponed, and meanwhile the maximum net lift coefficient increment achieved for the AETE (ΔC_L = 0.51) is slightly higher than that of the ACTE (ΔC_L = 0.50) at Mach 0.6. Compared to the ACTE, the AETE is found to have better control consistency at different operating velocities and better control stability when the Coanda jet is supersonic. Through careful consideration of the aerodynamic performance and the control effects, the most appropriate axial ratio for an AETE ellipse is within the interval from 1.5 to 2. Finally, the flow field instability phenomenon and the jet detachment induced by the supersonic Coanda jet are investigated. A self-sustained shock-wave instability phenomenon without jet detachment is first observed in this paper.

对于一系列不同的自由流马赫数和动量系数，通过数值评估了柯恩达后缘对机翼空气动力学性能的几何影响。具有圆形后缘（ACTE）的循环控制（CC）翼型被证明在低亚音速自由流速度（Mach = 0.1）下具有更好的控制效果。在高亚音速流条件下，具有椭圆形后缘（AETE）的CC翼型优于ACTE。的发生Ç _μ -stall为AETE大大推迟，同时为AETE实现的最大净升力系数增量（Δ ç_大号= 0.51）比ACTE的略高是（Δ Ç_大号= 0.50）时为0.6马赫。与ACTE相比，当柯恩达喷气超音速飞行时，发现AETE在不同的运行速度下具有更好的控制一致性，并具有更好的控制稳定性。通过仔细考虑空气动力学性能和控制效果，最合适的AETE椭圆轴比在1.5到2的范围内。最后，研究了超音速柯恩达射流引起的流场不稳定性现象和射流分离。本文首先观察到一种自持的冲击波失稳现象，没有喷流分离。