自然层流机翼的翼套试验及数值方法

Experiment and numerical simulation of natural laminar flow wing glove

基于某公务机飞行试验平台设计改装的自然层流翼套构型,以飞行试验为核心,开展了前期的数值方法和风洞试验研究。风洞试验和飞行试验均采用红外热像技术进行转捩探测。同时,使用基于线性稳定理论的eN方法对试验构型进行了数值模拟分析,探究攻角、压力分布形态对Tollmien-Schlichting(T-S)波失稳主导转捩的影响机制。研究结果表明,风洞试验构型在-2°~2°攻角范围内上翼面维持大范围的顺压力梯度,T-S波的增长得到了有效抑制,实现了50%c(弦长)以上的层流区,转捩发生在压力恢复区;在4°攻角工况下,头部出现明显的逆压力梯度,T-S波快速增长并发生失稳,转捩位置提前至20%c。飞行试验条件下的结果表明,压力分布形态对T-S波的影响机制与风洞试验一致;在高湍流度低雷诺数的风洞试验条件和低湍流度高雷诺数的飞行试验条件下,采用湍流度和Mack公式确定T-S波临界N因子,得到的转捩预测结果与试验结果均吻合较好,表明本文数值方法具有良好的预测精度和鲁棒性。

The preliminary numerical method and wind tunnel test research were conducted based on the modified natural laminar flow wing cover configuration of a business jet flight test platform, with the flight test as the core. Both wind tunnel tests and flight tests use the infrared(IR) thermal imaging technology for transition detection. Meanwhile, the LST-based eNmethod is used to carry out numerical simulation analysis of the experimental configuration, and to explore the influence mechanism of the angle of attack and pressure distribution on the dominant transition of Tollmien-Schlichting(T-S) wave instability. The research results show that the wind tunnel test configuration maintains a wide range of favorable pressure gradients on the upper surface in the angle of attack range of-2°-2°, and the T-S wave growth is effectively suppressed, achieving a chord length of more than 50% of the laminar flow region. In the laminar flow region, transition occurs in the pressure recovery area. An obvious inverse pressure gradient appears close to the leading edge at 4°, the T-S wave grows rapidly, and the transition position moves up to 20%c. The results under the flight test conditions show that the influence mechanism of the pressure distribution on the T-S wave is consistent with that in the wind tunnel test. Under the high turbulence and low Reynolds number wind tunnel test conditions, and the low turbulence and high Reynolds number flight test conditions, we use turbulence intensity and Mack formula to determine the critical N factor of the T-S wave, and the obtained transition prediction results are in good agreement with the experimental results, indicating that the numerical method has good prediction accuracy and robustness.