軸對稱鈍形體在工程實務上的應用十分廣泛，如潛艦、飛船、無人飛行載具甚至到飛彈外型皆有其應用，對於這些設計而言，如何了解軸對稱鈍形體之邊界層分離與流場結構為設計的重點之一，此外，使用被動控制方法降低其阻力或是穩定控制其流場亦是研究的重要考量。透過了解其周圍的流場結構、壓力分佈與阻力大小為工程設計與外型優化等提供重要依據。
本研究針對最大厚度為其特徵長度40%之淚滴型鈍形體(Teardrop, T40)於低速循環式水槽進行可視化實驗，於低速開放式噴流風洞進行可視化實驗與表面壓力量測，探討其於不同雷諾數下之流場結構與表面壓力之關係。此外，為降低T40模型對雷諾數的敏感特性，設計一T40x模型，此模型為於T40模型前方安裝一環形凸起物(Trip wire)，藉此被動控制方法，促使層紊流轉換提前發生，比較T40與T40x模型兩者之流場結構，並探討兩者對雷諾數的敏感程度。
於低速循環式水槽的可視化結果中觀察到，T40模型兩側x/c=0.28至0.65區間出現染液匯聚為焦點後的分離現象，並出現渦流溢放與不規則之尾流結構。透過點墨法實驗觀察，發現模型兩側亦出現渦流結構，但此渦流結構受模型攻角影響顯著，因此兩側大小、位置並不固定。在T40x模型中，由於安裝上trip wire，流場於trip wire處分離，並於x/c=0.2至0.28區間出現再接觸現象，將部分染液向trip wire處回流，形成類似幾何誘發分離泡（Geometry-Induced Separation Bubble, GISB）結構，另一部分染液則為向下游流動的附著流。
於開放式風洞進行油膜可視化與表面壓力量測，透過可視化結果發現，T40模型x/c=0.2處發生層流分離，並於x/c=0.2至0.28區間出現小尺度分離泡，且隨著雷諾數上升開始於模型後方出現紊流再接觸現象。在T40x模型實驗中發現，其流場結構穩定，於trip wire處出現分離泡(GISB)結構，並與水洞實驗流場結果相近，表示其受雷諾數影響較不明顯。透過平均壓力係數與擾動壓力係數標準差進一步驗證可視化實驗結果，並於不同雷諾數下將兩模型之結果進行比較。

In this study, the aerodynamic flow structures around a teardrop-shaped blunt body, referred to as the T40 model, were investigated. The T40 model was characterized by a chord length of 150 mm, and a maximum thickness of 60 mm, i.e. 40% of the chord length. Using a low-speed recirculating water channel, flow visualization experiments were conducted at a Reynolds number of Re = 1.77 × 10⁴; using a low-speed open-type wind tunnel, oil-flow visualization and surface pressure measurements were performed within a Reynolds number range of Re = 5.7 × 10⁴ to 2.21 × 10⁵. Based on the results obtained, flow structures around the model together with surface pressure distributions were examined over the range of Reynolds numbers studied. Moreover, a surface-mounted ring-type trip wire was installed on the fore-body surface of the model, which is referred to as the T40x model, to promote laminar-to-turbulent transition. A comparison between the T40 and T40x models was conducted with emphasis on the differences between their flow structures and the sensitivity to the Reynolds numbers studied.

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