研究採用慕尼黑大學所提供之標準車輛幾何模型，針對車輛尾部加裝擾流板前後之氣動性能進行系統性比較與分析。選用具備良好升力特性的 NACA 4412作為擾流板翼型剖面，研究內容涵蓋攻角變化對氣動參數的影響、翼端板厚度對渦流結構的控制效果、不同翼端板幾何設計之效能比較，以及於高速與低速不同來流條件下之升力與阻力表現差異。模擬結果顯示，加裝後擾流板的車輛模型在升阻比方面相較於未加裝時有顯著提升，特別是在高速流場條件下，更能有效降低尾流區的壓差與渦流強度，顯示擾流板在提升氣動效率與穩定性方面的潛力。此外，針對翼端板設計的探討亦顯示，適當設計之翼端板能有效削弱翼尖渦流對升力穩定性的負面影響，並改善尾流結構。然而若翼端板厚度設計不當，過厚可能導致迎風面阻力增大，顯示其幾何特性需謹慎考量。在速度區間的比較方面，研究發現高速條件下，擾流板所帶來的升阻比改善幅度遠高於低速條件，說明擾流板在高速行駛時對於氣流穩定性與尾部壓力分佈的影響更為顯著。綜上所述，本研究結果可作為車輛外型空氣動力優化設計之參考，特別是在高速行駛環境中，透過合理配置擾流板與翼端板，可有效提升車輛之操控穩定性與能源效率。

This study investigates the aerodynamic performance of rear spoilers and endplates through computational fluid dynamics (CFD) simulations on a three-dimensional vehicle model. The model is based on the standard DrivAer geometry developed by the Technical University of Munich, which has been widely used for aerodynamic research due to its realistic and modular design. A NACA 4412 airfoil, known for its favorable lift characteristics and moderate camber, was selected to design the spoiler.
The study systematically evaluates how different spoiler angles of attack, endplate thicknesses, and geometric configurations influence aerodynamic efficiency. Simulations are conducted under both low-speed (10–18 m/s) and high-speed (30–40 m/s) flow conditions to understand speed-dependent aerodynamic effects.
Results show that adding a properly designed rear spoiler improves the lift-to-drag ratio (Cl/Cd), particularly at higher speeds, where it effectively reduces adverse pressure gradients and mitigates flow separation at the rear of the vehicle. The presence of endplates further enhances aerodynamic stability by minimizing the strength of tip vortices and promoting cleaner airflow reattachment. However, excessively thick endplates increase frontal area and drag, which in turn degrades aerodynamic performance.
High-speed conditions exhibit more pronounced improvements in Cl/Cd than low-speed scenarios due to the relatively lower influence of skin friction and a greater contribution from pressure drag. These findings offer practical guidance for optimizing spoiler and endplate designs to enhance vehicle stability and efficiency, especially in high-speed automotive applications.

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