后缘连续变弯度对跨声速翼型气动特性的影响

针对后缘连续变弯度对跨声速翼型气动特性的影响进行了研究。首先不考虑翼型后缘连续变弯度,基于搭建的优化设计系统对跨声速翼型进行气动减阻优化设计,通过添加不同的约束优化得到两种跨声速翼型:无激波翼型和超临界翼型。然后在这两种翼型的基础上,以后缘偏转角度为设计变量、以阻力系数最小为目标,针对不同的升力系数分别进行优化设计,并根据优化结果深入分析后缘连续变弯度对这两种翼型极曲线特性的影响机理。优化结果表明:无激波翼型与超临界翼型相比,其设计点处的气动特性较好,但鲁棒性较差;升力系数小于设计升力系数时,应用后缘连续变弯度后,无激波翼型的极曲线特性明显提高,减阻最高达到3.9%,而超临界翼型的极曲线特性提高不明显;升力系数大于设计升力系数时,应用后缘连续变弯度后,无激波翼型和超临界翼型的极曲线特性都明显提高,减阻分别达到2.4%~18.1%和1.7%~13.2%。

Influence of continuous trailing-edge variable camber on aerodynamic characteristics of transonic airfoils

The influence of continuous trailing-edge variable camber on the aerodynamic characteristics of transonic airfoils is investigated. Before the continuous trailing-edge variable camber is considered, the aerodynamic drag reduction optimization design of the transonic airfoil is carried out based on the optimization design system constructed in this paper. With different constraints added, two kinds of transonic airfoils are obtained, namely the shock-free airfoil and the supercritical airfoil. Then the optimization design is conducted based on the two airfoils at different lift coefficients, by taking the deflection angle of the trailing-edge as the design variable and the minimum drag coefficient as the objective. And the effect of the continuous trailing-edge variable camber on the drag polar of these two kinds of transonic airfoils is investigated and analyzed according to the optimization results. The results of the optimization design show that the aerodynamic characteristics of the shock-free airfoil are better than those of the supercritical airfoil at the design point, but the robustness is worse. Besides, when the lift coefficient is lower than the design lift coefficient, the drag polar characteristic of the shock-free airfoil can be improved greatly with the continuous trailing-edge variable camber applied, thus the drag coefficient is reduced by up to 3.9%. However, the situation of supercritical airfoil is different. The results also demonstrate that when the lift coefficient exceeds the design lift coefficient, the continuous trailing-edge variable camber method can significantly improve the drag polar performance of both airfoils with the drag coefficients of them being reduced by 2.4%-18.1% and 1.7%-13.2% respectively.