本研究針對開源之計算流體力學（CFD）軟體SU2進行一系列模擬與外型優化分析。研究主要目標為透過車輛模型外型之幾何變形設計，降低空氣阻力以減少能源的消耗，進而提升氣動效率與燃油使用率，達到降低碳排放與減輕環境負擔之效益。
使用SU2進行優化之前，須先驗證其模擬準確性與可靠性。因此使用SU2與商業軟體ANSYS Fluent求解不可壓縮雷諾平均納維-斯托克斯方程式（Incompressible Reynolds-Averaged Navier–Stokes Equations），並同時使用Shear Stress Transport（SST）k-ω紊流模型分別對二維及三維DrivAer Fastback車體模型進行模擬與比對。比對內容包含升力係數（Cl）、阻力係數（Cd）及表面壓力係數（Cp）分佈等關鍵氣動參數，藉此探討兩種軟體模擬結果間之差異與誤差，驗證SU2在車輛外型氣動優化應用中的準確性與可行性。在此基礎上，進一步利用SU2所提供之優化工具，透過伴隨運算子（adjoint operator）進行幾何外型變形與優化設計，有效提升車體之空氣動力性能。
綜上所述，SU2不僅具備可靠之模擬能力，亦能結合高效率的形狀優化流程，為車輛氣動設計提供一套具準確性、靈活性與可擴展性之數值工具，具備實際工程應用之潛力。

This study presents a series of simulations and aerodynamic shape optimization analyses using the open-source computational fluid dynamics (CFD) software SU2. The primary objective is to reduce aerodynamic drag (Cd) through geometric modifications of a vehicle model, thereby improving aerodynamic efficiency, enhancing fuel economy, and ultimately reducing carbon emissions and environmental impact.
Prior to performing the shape optimization, the accuracy and reliability of SU2 are validated. Both SU2 and the commercial solver ANSYS Fluent are used to solve the incompressible Navier-Stokes equations with the Shear Stress Transport (SST) k-ω turbulence model. Simulations are conducted on both two-dimensional and three-dimensional DrivAer Fastback vehicle models. Key aerodynamic parameters including lift coefficient (Cl), drag coefficient (Cd), and surface pressure coefficient (Cp) distributions—are compared to assess the discrepancies between the two solvers and to verify the feasibility of using SU2 for vehicle aerodynamic simulations.
Building upon this validation, SU2 built-in optimization framework is employed to perform shape refinement using adjoint-based sensitivity analysis and geometric deformation. The optimization process effectively improves the aerodynamic performance of the vehicle through iterative shape adaptation.
In conclusion, SU2 demonstrates not only reliable simulation capabilities but also an efficient and flexible optimization framework, highlighting its potential as a powerful and extensible numerical tool for practical aerodynamic design applications in the automotive industry.

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