Passive Flow Control over Flexible Non-Slender Delta Wings
Passive Flow Control over Flexible Non-Slender Delta Wings
复制标题
柔性非细长三角翼的被动流量控制
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
I. Gursul
中科院分区：
文献类型：
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作者：
G. Taylor;A. Kroker;I. Gursul
在一系列非细长三角翼上的力测量已经证明，与类似几何形状的刚性机翼相比，柔性机翼具有增强升力和延迟失速的能力。这项工作扩展了最近研究的结果，包括具有一系列后掠角的三角翼。结果表明，在具有最小前缘后掠角的机翼上观察到最大的升力增强。此外，对于所考虑的唯一细长机翼，没有观察到升力增强，这表明，这是造成这种现象的一个根本不同的流动特征，这种流动发生在小后掠角机翼上。所有有关机翼的均方根升力和滚转力矩系数随迎角的变化表明，在增升区，机翼是以反对称结构模态振动的。这支持了以前关于50°机翼的证据，表明同样的情况。此外，半翼模型的实验表明，这种机翼不经历升力增强，因此反对称振动可能是升力增强存在的必要条件。还测量了某些机翼的翼尖偏转，结果表明，细长机翼比非细长机翼经受了高得多的时均偏转，尽管它也经受了低得多的抖振水平。PIV和LDV测量结果表明，在相同迎角下，柔性和刚性机翼在过失速区的表面流动存在显著差异。在小后掠角机翼上实现柔性，将导致剪切层在比刚性机翼上观察到的更高的迎角下继续再附着。
∗† ‡ Force measurements over a range of non-slender delta wings have demonstrated the ability of a flexible wing to enhance lift and delay stall compared with a rigid wing of similar geometry. The work has extended the results of a recent study to include delta wings with a range of sweep angles. It has been shown that the greatest lift enhancement was observed over the wing with smallest leading edge sweep. Additionally for the only slender wing considered no lift enhancement was observed indicating that it is a feature of the fundamentally different flow that occurs over low-sweep wings that is responsible for the phenomenon. The variation of RMS lift force and rolling moment coefficients with incidence for all the wings concerned suggest that the wings are vibrating in an antisymmetric structural mode in the lift enhancement region. This supports previous evidence for the 50° wing that suggests the same. Further, experiments of a half-wing model suggest that this wing does not undergo lift enhancement, and as such it may be that the antisymmetric vibration is a necessary condition for the lift enhancement to exist. Wing-tip deflections for some of the wings were also measured, which showed that the slender wing undergoes much higher time-averaged deflections than the non-slender wings, although it also experiences a much lower level of buffet. PIV and LDV measurements have demonstrated the striking difference between the surface flows over the flexible and rigid wings in the post-stall region at the same incidence. Implementing flexibility on a low sweep wing results in continued reattachment of the shear layer to much higher incidences than would otherwise be observed over a rigid wing.