本研究之目的為探討渦流產生器對機翼動態失速之影響，並藉由商業CFD套裝軟體進行模擬，數值方法使用RANS之SST k-ω紊流模型計算，機翼俯仰運動則運用重疊網格(overset mesh)模擬。本論文第一部份透過田口方法對渦流產生器進行參數最佳化，選定之參數有四種，分別為鰭片與自由流之夾角(β)、每兩對渦流誘發鰭片之間距(D)、渦流誘發鰭片之間距(d)和渦流誘發鰭片與機翼翼前緣之位置(XVG)，並使用L9直交表進行數值模擬。分析結果顯示，在α=20°下，最佳參數配置為β=15°、D/h=8、d/h=2、XVG/c=30%，影響程度依序為XVG/c、D/h、d/h和β，經模擬驗證後可得升力係數的最佳值為1.533，與預測值相差0.6%。此外，不同攻角下的模擬結果顯示，最佳參數配置VG在低攻角時，升力略遜於未安裝VG，但差距僅在3%以內，並在α=20°時，安裝VG可使升力增加12.8%；在阻力方面，安裝VG之機翼在所有攻角下的阻力均高於未安裝。並且無論是否安裝鰭片，機翼皆在α=22°時於上反部份發生翼前緣失速。
在本論文的第二部分探討不同俯仰週期與安裝VG對升力效應遲滯效應之影響，並探討其流動結構。其中未安裝VG之機翼進行短週期(5秒)與長週期(10秒)之俯仰運動；安裝VG則執行短週期(5秒)俯仰運動，並分別探討不同週期和安裝VG對遲滯效應之影響，以上結果以升力係數對攻角圖與Q-criterion等值面呈現。最終結果表明，兩組週期並未對流場結構產生明顯差異，但仍可觀察到隨著週期延長，升力係數的遲滯效應有所減少。此外，安裝鰭片對於動態失速之升力係數提升效果不佳。而在下行程時，鰭片產生之渦流的相互干擾增加了遲滯效應，並且安裝鰭片對於翼尖處之流場回貼幫助不明顯，但在動態失速發生後，升力係數下降速率相對於未安裝緩慢。因此，安裝鰭片仍然能夠為飛機在失速後提供一定的操作空間，使飛行員在失速後可採取適當的措施來恢復飛機的正常飛行。

This research investigates the influence of vortex generators (VGs) on wing dynamic stall using CFD. The first part of the study optimizes VG parameters through the Taguchi method, considering four variables: VG angle (β), spacing between VG pairs (D), spacing within VG pairs (d), and VG position relative to the wing's leading edge (XVG). Results show that at α=20°, the optimal VG configuration is β=15°, D/h=8, d/h=2, and XVG/c=30%. The simulation matches predicted lift coefficient within 0.6%. VGs slightly reduce lift at low angles but increase lift by 12.8% at α=20°. VG-installed wing experiences higher drag at all angles, and leading-edge stall occurs at α=22°. The second part analyzes different pitching periods and VG effects on lift hysteresis and flow structures. The flow structures show no significant differences with varying periods, but hysteresis decreases with longer periods. VGs offer limited lift coefficient enhancement during dynamic stall and help slow the lift descent rate after stall occurrence. Thus, VGs provide operational recovery margins for aircraft encountering stall conditions.

[1] W. contributors. "Micro Dynamics vortex generators mounted on the wing of a Cessna 182K." Wikipedia, The Free Encyclopedia.https://en.wikipedia.org/w/index.php?title=Vortex_generator&oldid=1146446723 (accessed.
[2] W. J. Mccroskey, K. W. Mcalister, L. W. Carr, and S. L. Pucci, "An Experimental Study of Dynamic Stall on Advanced Airfoil Sections. Volume 1. Summary of the Experiment," 1982.
[3] L. W. Carr, "Progress in analysis and prediction of dynamic stall," Journal of Aircraft, vol. 25, no. 1, pp. 6-17, 1988, doi: 10.2514/3.45534.
[4] K. Mulleners and M. Raffel, "Dynamic stall development," Experiments in Fluids, vol. 54, no. 2, 2013, doi: 10.1007/s00348-013-1469-7.
[5] M. R. Visbal and D. J. Garmann, "Dynamic Stall of a Finite-Aspect-Ratio Wing," Aiaa Journal, vol. 57, no. 3, pp. 962-977, Mar 2019, doi: 10.2514/1.J057457.
[6] T. O. Yilmaz and D. Rockwell, "Flow structure on finite-span wings due to pitch-up motion," Journal of Fluid Mechanics, vol. 691, pp. 518-545, 2012, doi: 10.1017/jfm.2011.490.
[7] J. C. Lin, "Review of research on low-profile vortex generators to control boundary-layer separation," Progress in Aerospace Sciences, vol. 38, no. 4-5, pp. 389-420, 2002.
[8] O. M. Fouatih, M. Medale, O. Imine, and B. Imine, "Design optimization of the aerodynamic passive flow control on NACA 4415 airfoil using vortex generators," European Journal of Mechanics B-Fluids, vol. 56, pp. 82-96, Mar-Apr 2016, doi: 10.1016/j.euromechflu.2015.11.006.
[9] B. R. Kelly, "<Vortex Generator Flow Control for an Upper-Surface Blown Aircraft Wing with an Extended Coanda Flap>," Master, Oregon State University, 2022.
[10] G. Godard and M. Stanislas, "Control of a decelerating boundary layer. Part 1: Optimization of passive vortex generators," Aerospace Science and Technology, vol. 10, no. 3, pp. 181-191, 2006, doi: 10.1016/j.ast.2005.11.007.
[11] D. Baldacchino, C. Ferreira, D. D. Tavernier, W. A. Timmer, and G. J. W. van Bussel, "Experimental parameter study for passive vortex generators on a 30% thick airfoil," Wind Energy, vol. 21, no. 9, pp. 745-765, 2018, doi: 10.1002/we.2191.
[12] F. R. Menter, "Two-equation eddy-viscosity turbulence models for engineering applications," AIAA Journal, vol. 32, no. 8, pp. 1598-1605, 1994/08/01 1994, doi: 10.2514/3.12149.
[13] W. P. Jones and B. E. Launder, "The prediction of laminarization with a two-equation model of turbulence," International Journal of Heat and Mass Transfer, vol. 15, no. 2, pp. 301-314, 1972/02/01/ 1972, doi: https://doi.org/10.1016/0017-9310(72)90076-2.
[14] D. C. Wilcox, "Formulation of the k-w Turbulence Model Revisited," AIAA Journal, vol. 46, no. 11, pp. 2823-2838, 2008/11/01 2008, doi: 10.2514/1.36541.
[15] C. Bak, P. Fuglsang, J. Johansen, and I. Antoniou, "Wind tunnel tests of the NACA 63-415 and a modified NACA 63-415 airfoil," Risø National Laboratory,, 01/01 2000.
[16] K. W. Mcalister, L. W. Carr, and W. J. Mccroskey, "Dynamic stall experiments on the NACA 0012 airfoil," 1978.
[17] H. Fukumoto, H. Aono, T. Nonomura, A. Oyama, and K. Fujii, "Significance of Computational Spanwise Domain Length on LES for the Flowfield with Large Vortex Structure," in 54th AIAA Aerospace Sciences Meeting, (AIAA SciTech Forum: American Institute of Aeronautics and Astronautics, 2016.