臺灣博碩士論文加值系統

本研究探討在低雷諾數下無掠角的NACA0012機翼的表面流場及尾流區
流場的動態特性.運用表面油膜流場觀察法觀察表面流場的行為,並使用熱
線探針於尾流區以偵測非穩態結構的頻率特性.在弦長雷諾數/根攻角圖面
上可以劃分出五個表面流場的特徵模態.在迎風面雷諾數/根攻角圖面上可
以劃分出四個尾流區渦旋流逸的特徵模式,這些特徵模式的演變,與表面流
場的行為有密切的關係.本文詳細探討渦旋流逸在各模式的動態行為,並比
較低與高擾動自由流的影響.

Characteristics of unsteady flow on the suction surface and
in the wake re-gion of a NACA0012 cantilever wing operated in
low-Reynolds number are studied.Surface oil-flow technique is
employed to visualize the flow patterns on the suction surface.
Hot-wire anemometers are used to characterize the frequency
domain of the unsteady flow structure in the wake region. Five
characteristicsurface flow modes are classified in the domain of
chord Reynolds number androot angle of attack. Vortex shedding
in the wake region can be classified intofour characteristic
modes. Evolution of characteristic vortex shedding modes are
closely related to the behaviors of the surface flow. Dynamic
behaviors ofvortex shedding in different modes are discussed in
detail. Effects of enhanc-ing turbulence intensity in free
stream are also discussed.