前掠翼纵向气动特性的实验研究

 本文基于风洞测力、测压、等试验结果,研究了前掠翼的气动力特点,并与相应的后掠翼做了比较。研究了改进前掠翼根部流动的措施和改进后的收益。在低速情况下,根部适当后掠可以较好地改善前掠翼根部的流动,获得较大的气动力收益。配置鸭翼可以进一步改善前掠翼根部的流动,得到更大的升阻比。例如,根部适当后掠的前掠翼（整流翼）配置鸭翼以后,C_y=0.5时的升阻比可比边条后掠翼配置鸭翼（两种布局升力面面积相等）的升阻比提高24％。 前掠翼在跨音速有较小的零升阻力和诱导阻力。当M_α=1.1,α=6°时,前掠翼的诱导阻力要比后掠翼的小12.5％。低速时改善根部流动的措施在跨音速时仍然有效。前掠翼以及根部适当后掠的前掠翼（整流翼）配置合适的鸭翼,也可使前掠翼的高速性能得到较大改善。

EXPERIMENT INVESTIGATION ON LONGITUDINAL CHARACTERISTICS OF THE FORWARD SWEPT WING

In this paper longitudinal aerodynamic characteristics of a forward swept wing are discussed on the basis of wind tunnel testings on aerodynamic forces and pressures.The results are compared with the results of associated back swept wing.The investigation results show that the aerodynamic performance for forward swept wing is increased by improving the separation flowfield over the inboard portion of the win|. The low speed investigation discovers that the strake,the leading edge flap and the fairings of aft swept inboard can improve the characterstics of for ward swept wing. At the low and moderate angles of attack the effectiveness of aft swept inboard fairings is more significant and one would gain more aerodynamic benifit.The downwash and separated vortex flow from the canard can further improve the inboard flowfield over forward swept wing with or without aft swept inboard fairing.Hence,the lift-drag characteristics of the closed-coupled canard configuration with forward swept wing having an aft swept inboard fairing are obviously better than that of the canard configuration with aft swept wing within the same range of testing angles of attack. It is also found better than that of the canard configuration with strake aft swept wing with lift-drag characteristics upto Cy=1.05 （a is about 17 deg） For example,when Cy=0.5,the lift-drag ratio is increased by 24%,and the curve of pitching moment for the closed-coupled canard configuration with forward swept wing having an aft swept inboard fairing becomes more linear.In transonic regime,the forward swept wing possesses less zero-lift drag and lift induced drag than the aft swept wing.When Ma = l.1 a = 6, the lift induced drag of the forward swept wing is 12.5% less than that of the aft swept wing.The characteristics of the forward swept wing can still be improved at these speeds with the strake and the aft swept inboard fairing, in which the aft swept inboard fairing gives better performance.The maximum lift-drag ratio is increased by 10% in the investigated range of Mach numbers. The forward swept with the canard can also provide more improvement to the high speed characteristics.