Lift Disturbance Cancellation with Fast-Flap Actuation
Lift Disturbance Cancellation with Fast-Flap Actuation
复制标题
通过快速襟翼驱动消除升力干扰
DOI：
10.2514/6.2018-3090
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Matthew Rockwood
中科院分区：
文献类型：
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作者：
A. Medina;Maziar S. Hemati;Matthew Rockwood
本文给出了在Re = 40K水洞中对NACA 0006机翼简单襟翼快速偏转的实验结果，以研究襟翼偏转设计，以消除整个机翼的强制倾伏运动引起的升力瞬态。在一段时间内，从八个对流时间到一个对流时间，骤降被认为是一个垂直扰动，或“阵风”。襟翼偏转历程最初是从Theodorsen的非定常襟翼运动公式推导出来的，从中可以得到相位和振幅信息。理论推导采用了附着流、平面尾流和无前缘涡的标准假设。对纯俯冲、纯襟翼偏转和组合翼型俯冲和襟翼偏转运动的前元件和机翼襟翼升力的实验数据测量值进行了检验。后者显示了高达87%的升力取消，验证了Theodorsen公式的有限但实质性的适用性。通过构造翼型倾伏和襟翼偏转的经验模型，寻求对升力抵消理论公式的改进。翼型倾伏和襟翼偏转的经验模型是相互独立地建立起来的，它们的叠加被用来近似组合倾伏和偏转运动中的总升力。结果表明，虽然经验模型方法与Theodorsen模型的无粘理论相似，但经验模型在抑制俯冲诱导的前缘涡方面更有效。
Experimental results examining a rapidly-deflecting simple flap of a wall-to-wall NACA 0006 wing in a water tunnel at Re = 40k are presented for a survey of flap deflections designed to negate the lift-transient from an imposed plunge motion of the entire wing. The plunge, over a period ranging from eight convective times to one convective time, is regarded as a vertical disturbance, or a “gust”. The flap deflection history is initially derived from Theodorsen’s formula for unsteady flap motions, from which one obtains phase and amplitude information. The theoretical derivation makes the standard assumptions of attached flow, planar wake, and no leading edge vortices. Experimental data measurements of lift on the fore-element and the flap of the wing are examined for pure-plunge, for pure flap deflection, and for the combined airfoil plunge and flap deflection motion. The latter shows up to 87% of lift cancellation, verifying the limited, but substantial applicability of Theodorsen’s formula. Improvements over the theoretical formulation of lift cancellation are sought by constructing empirical models for both airfoil plunge and flap deflection. The empirical models for airfoil plunge and flap deflection are constructed independent of one another and their superposition is employed to approximate the total lift in combined plunge and deflection motions. It is shown that although the empirical model approach performs similar to the inviscid theory of Theodorsen’s model, the empirical model proves more effective in suppressing the leading-edge vortex induced in plunge.