仿生覆羽控制固定翼无人机流动失速风洞实验  

Wind tunnel experiment on control of stalling flow of fixed wing UAV with bionic coverts

作　　者：刘一宏 马兴宇 巩绪安 黄逸军 王勇[4] 姜楠[1] LIU Yihong;MA Xingyu;GONG Xu’an;HUANG Yijun;WANG Yong;JIANG Nan(Tianjin Key Laboratory of Modern Engineering Mechanics,School of Mechanical Engineering,Tianjin University,Tianjin 300354,China;National Key Laboratory of Science and Technology on Aerodynamic Design and Research,NPU,Xi’an 710072,China;State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China;Key Laboratory of Aerodynamic Noise Control,China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]天津大学机械工程学院天津市现代工程力学重点实验室,天津300354 [2]西北工业大学翼型、叶栅空气动力学国家级重点实验室,西安710072 [3]西南交通大学牵引动力国家重点实验室,成都610031 [4]中国空气动力研究与发展中心气动噪声控制重点实验室,绵阳621000

出　　处：《空气动力学学报》2023年第10期52-60,I0002,共10页Acta Aerodynamica Sinica

基　　金：国家自然科学基金(11902218,11972251,12172242,12272265,12202310);翼型、叶栅空气动力学国家级重点实验室稳定支持经费项目(61422010301);气动噪声控制重点实验室开放课题(ANCL20230108);西南交通大学牵引动力国家重点实验室开放课题(TPL2306);中德合作研究小组计划(GZ1575);天津市研究生科研创新项目资助(2022SKY058)。

摘　　要：研究了基于鸟类仿生学设计的人工柔性锯齿形覆羽在平直机翼大攻角失速流动控制中的作用。实验在天津大学低速回流式低湍流度风洞中进行,以展长1.0 m、弦长300 mm的NACA0018平直机翼模型在15°攻角条件下产生的失速流动作为研究对象,基于弦长的雷诺数为Re=5.1×10^(5)。实验中,将柔性覆羽沿展向分别安装在机翼上翼面的不同位置处,利用单丝热线风速仪扫掠测量机翼尾流的速度信号,并与无控制工况的平均速度、脉动速度、功率谱密度等对比。实验结果显示:在20%c位置工况中,柔性覆羽装置吸收来流中的能量,随上翼面流动自适应振动;在80%c位置工况中,柔性覆羽处于准平衡位置,并伴随微小振动。两种工况的尾流区平均速度亏损恢复明显,同时前缘剪切层和尾缘剪切层中的湍流脉动均明显降低,两种工况均实现了流动失速的有效控制。进一步的功率谱密度和离散小波分析显示,柔性覆羽的自适应振动能有效地抑制剪切层中低频、大尺度结构(fc/U∞<1),并将其转化为高频、小尺度结构(fc/U∞≈3),增强了前缘剪切层和尾缘剪切层的相干性。该研究结论揭示了类鸟类柔性覆羽在平直机翼大攻角失速流动控制中的作用机理。In this paper,the experimental study of stall control of a straight wing by bio-inspired flexible serrated coverts was conducted in the subsonic close-loop low-turbulence wind tunnel in Tianjin University.The NACA0018 wing model had a chord of 300 mm and a span of 1.0 m,and it was installed at the angle of attack of 15°,resulting in a stalling flow phenomenon in the wake.The chord-based Reynolds number was Re=5.1×10^(5).The spanwise coverts were fixed at multiple positions on the upper surface,and the resulting wake flow velocity was measured with the hot-wire anemometer.The averaged velocity,fluctuating velocity and power spectral density etc.were compared between the cases with and without control.Experimental results show that the coverts at the 20%chord adaptively flap with the flow,whereas the coverts at the 80%chord slightly flutter at a quasi-equilibrium position.The averaged velocity loss in the wake zone is recovered obviously in the two conditions,and the turbulent fluctuation in the shear layers of both the leading and trailing edges decreases obviously.The control effect on the stalling flow is realized under both conditions.Moreover,the power spectral densities and discrete wavelet analyses reveal that the adaptive coverts suppress the low/medium-frequency large-scale flow structures(fc/U∞<1),and convert them into high-frequency small-scale ones(fc/U∞≈3),leading to higher spectral coherence between the leading edge and trailing edge shear layers.The mechanism of bird coverts in stalling flow control at high angle of attack of a straight wing is thus revealed.

关 键 词：仿生学 风洞实验 覆羽 失速流动 流动控制 热线风速仪 

分 类 号：Q811.6[生物学—生物工程] O357.5[理学—流体力学]