前缘和转轴影响翼摇滚特性的数值模拟

采用耦合求解N-S方程和Euler刚体动力学方程的数值模拟方法研究80°后掠三角翼摇滚特性,讨论机翼前缘构型和滚转轴位置对三角翼摇滚特性的影响。N-S方程的离散采用Roe格式和含双时间步的LU-SGS方法,刚体动力学方程的离散采用二阶精度的差分方法,通过交替求解流动和运动控制方程组的耦合策略,模拟80°后掠三角翼自激摇滚的非定常过程。针对转轴安装于上表面的细长三角翼,研究前缘上削尖、下削尖和双面削尖三种构型的翼摇滚特性,分析前缘构型对摇滚振幅及分岔攻角的影响。考虑到上削尖和下削尖构型在翻转后相当于前缘构型互换但转轴位置不同,进一步考察了滚转轴位置对三角翼摇滚特性的影响。结果表明:在一定的攻角下,三种不同前缘构型的三角翼均能形成大幅自维持的摇滚现象,其中上削尖前缘的三角翼振幅最大,双面削尖前缘次之,下削尖前缘三角翼振幅最小;攻角增大到30°以后,双面削尖和上削尖前缘的三角翼会发生翻转现象,翻转180°以后维持等幅振荡。

Numerical investigation of wing rock characteristics influenced by leading edge and roll-axis

Numerical investigation of a 80°swept delta wing rock characteristics was presented by solving N-S (Navier-Stokes) equations coupled with Euler rigid-body dynamics equations, and the influences of leading edge configuration and roll-axis installation were discussed. For the unsteady simulation of self-induced wing rock phenomenon, the Roe scheme and LU-SGS method with dual-time stepping approach were employed for NS equations discretization, the second order differential scheme was employed for Euler rigid-body equation discretization, and the loose-coupling approach for flow control equations and movement control equations was implemented. For the delta wing with a roll-axis located on the upper surface, three leading edge configurations, including upper beveled, lower beveled and double beveled were used for evaluating the influence on the amplitudes and bifurcation angles of delta wing rock. In view of the configuration equivalence of upper beveled delta wing and lower beveled delta wing, the influence of roll-axis installation was evaluated also. The results show that under a certain attack angle, all of the three delta wings with different leading edge configuration establish large and self-retained wing rock amplitudes, and the largest amplitude is observed with upper beveled delta wing, the double beveled delta wing takes the second place and the amplitude of lower beveled delta wing reaches the least degree. For the attack angle of 30°, the roll-over phenomena are observed at the delta wings with upper and double beveled leading edge configuration, and when the roll angle reaches to 180°, the oscillation amplitude remains unchanged.