戰鬥機與民航機在巡航時所需的升力來源不同，主要是因為兩者所需的飛行條件不同，民航機強調的是穩定飛行，而戰機需要的則是高性能的飛行，如高攻角爬升以及空中纏鬥性能等，這樣的條件就需要更好的升力表現，意即機翼上下表面的壓差要更大，因此在戰機上的空氣動力特性主要受翼表面上所產生的渦流結構與分離流影響。然而為了增加機翼表面上的渦流穩定性，在過去許多研究中發展了如渦流產生器(Vortex generator)、翼身融合(Blended wing)或是翼根延伸(Leading edge root extension，LEX、LERX)等裝置來延後表面分離流的位置或是維持機翼表面的渦流結構，以增加在高攻角時的升力表現。
本實驗將以流場可視化與粒子影像測速儀進行翼根延伸的模型-美國國家航空暨太空總署(NASA)的TP-1803流場觀察，用視流實驗洞悉機翼表面上定性的渦流結構形成與發展，並利用流場的量化資料來釐清渦流結構的特性，以了解主翼前的輔助翼所產生的渦流對於整體的流場影響。
實驗內容將進行TP-1803模型的視流實驗，將使用點墨法與油膜法觀察翼表面的分離線位置與漸近流線的方向，以及染液注射法來觀察機翼表面上的渦流結構的形成與變化。並佐以粒子影像測速儀量測機翼上的流場速度分布、速度向量以及渦度分布來量化渦流結構中的物理特性，並加以統整以了解不同攻角下渦漩潰散發生的位置，探討渦流間的交互作用。

Fighters and civil aircraft require different sources of lift during cruise because of the distinct flight requirements. The primary condition of civil aircraft is flight stability, whereas fighter aircraft requires high-performance flight, such as high angle of attack(AOA) climb and dogfight ability, such conditions require better lift performance, which means that the pressure difference between the upper and lower surfaces of the wing is greater. Therefore, the vortex structure and separated flow dominate the aerodynamic characteristics of fighters mainly. In order to increase the vortex stability on the wing surface, researchers developed some devices such as vortex generator, leading edge root extension(LEX, LERX, strake), or blended wing to postpone the separated positions of surface flow or maintain the vortices structures on wing surface, so that increases the lift performance of fighters at high angle of attack.
In this research, flow visualization and particle image velocimetry (PIV) was conducted to understand the flow field of the LEX model, NASA TP-1803. Observe the formation and development of the vortex structures in flow visualization images to realize the qualitative characteristics and measure velocity on the wing surface to analyze the quantitative data of vortex structures around NASA TP-1803 model, understanding the flow field effects result from the strake vortex.

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