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中文核心期刊

基于相交不稳定性的尾流自消散机翼实验研究

EXPERIMENTAL STUDY ON SELF-DISSIPATION-WAKE WING BASED ON INTERACTIVE INSTABILITY

  • 摘要: 飞机尾流是复杂的流动现象,相关控制的研究常采用简化模型,抓住主要矛盾进行尾流不稳定性的学术探索. 采用结构化矩形机翼模型,通过添加扰流片来模拟襟翼的一种作动方式,引入一对与主翼涡反向的小涡,以期诱发尾涡的瑞利-路德维希相交不稳定性. 改变模型在水槽中的拖曳速度以及机翼攻角,采用粒子图像速度场仪定量研究单主翼尾涡发展特性以及双涡相互作用特性. 研究表明,未添加扰流片时,尾涡环量在45 个翼展内相对于初始环量衰减了10%;而添加了扰流片的实验中,在较好的实验参数组合情况下,主翼尾涡环量较初始环量降低35%~45%. 结果表明添加适当扰流片产生的反向小涡能诱发与主翼尾涡的相交不稳定性,在尾流涡系中引入自消散机制,加速机翼尾涡的消散过程,达到提早消弱尾涡的目的.

     

    Abstract: Aircraft wake vortex is an inherent co-existing phenomenon connecting to the lift-generating mechanism. It exhibits in the form of tri-dimensional vortex generated by limited wings at the wing tip, which would introduce great hazard to following flight and threaten to the flight safety. Based on a simplified rectangular airfoil, two rectangle-plate flaps were attached onto the airfoil to construct a counter rotating four-vortex wake system to induce the Rayleigh-Ludwig instability of the wake, resulting in a premature breakdown of the wake vortex. The research was performed in Fluid Mechanics Lab in Xiamen University, which equipped with a towing tank and a Particle Image Velocimetry system. Under different experimental conditions, in terms of towing speed and attack angle, the wake vortex development of the test model, both with and without flaps, as well as the circulation analysis, were acquired. The study demonstrated that the decrease in circulation was 35% to 45% in 45 wingspans when flaps were introduced, whereas the counterpart of the baseline airfoil, without flaps, was only 0% to 10%, which revealed the application possibility of Rayleigh-Ludwig instability in alleviating the wake vortex.

     

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