求解非定常空气动力系数主导极点的近似方法

 在计算与风洞实验的基础上, 提出了机翼剪切翼梢气动布局, 对平面形状与翼型进行了 优化设计, 达到了巡航状态与爬升阶段较高的增升减阻要求。计算采用涡格面元法与涡升力展向 分布吸力比拟法相结合的方法, 既能考虑气动力的非线性因素, 又有较高的计算精度与速度。计 算结果与实验数据十分吻合。通过分析得到, 在矩形翼翼梢处增加具有较大前缘后掠角的梯形剪 切翼梢有不仅增加机翼展弦比, 且可改变展向环量分布, 使其接近椭圆分布; 剪切翼梢上的前缘 涡可抑制翼端涡的作用(使翼端涡强度变弱) , 并在剪切翼梢上产生附加升力。

APPROXIMATION ON THE DOMINANT POLES OF UNSTEADY AERODYNAMIC COEFFICIENT

Based on computation and windtunnel test, a rational aerodynamic configuration ofsheared wingtip is posed, including optimum design of planform and airfoil, and the higher demands of increased lift and reduced drag at cruise and in climb are met. A method combining both the panelvo rtexlat tice method and the suction analogy method of the vo rtexlift distribution in the span direction is adopted, which may account for the nonlinear aerodynamics and raise the calculation precision and speed. The computation and experimental data are in fair agreement. After analyses, it is obtained that a sheared w ingtip with highly leadingedge sweptangle, mounted on the tip of a rectangular wing, can make the spanwise circula ion distribution of the wing close to anellip tical distribution, and the leadingedge separated vortex on the sheared w ingt ip mayrest rain the trailing vortex on the wing tip ( to cause the trailing vortex st rength to drop ) , and may produce additional lift on the sheared wing tip.