Experimental Flow Visualization of a NACA 4412 Airfoil Equipped with a 60° Forward Wingtip Fence in a Subsonic Wind Tunnel
DOI:
https://doi.org/10.71225/jstn.v2i4.120Keywords:
Wingtip fence , NACA 4412, Wingspan, Angle of attack, Wind tunnelAbstract
Wingtip-induced three-dimensional flow accelerates boundary-layer separation and amplifies vortex-related losses, particularly at low Reynolds numbers. This study experimentally investigates the surface-flow characteristics of a NACA 4412 airfoil equipped with a 60° forward wingtip fence under subsonic conditions. Wind-tunnel experiments were conducted at a freestream velocity of 10 m/s (Re ≈ 2.3 × 10⁴) over angles of attack ranging from 0° to 17°. Oil-flow visualization and tuft visualization were employed to identify laminar–turbulent transition (Xt), separation (Xs), and reattachment (Xr) locations and to qualitatively assess near-surface flow stability. Compared with the baseline airfoil, the 60° forward wingtip fence systematically shifted separation downstream and delayed vortex development in the pre-stall regime. At 10°, the separation point moved from approximately 20 mm (baseline) to 30 mm, while reattachment shifted from 30 mm to 45 mm. Tuft observations indicate that significant vortex formation appeared earlier in the plain configuration (from 12°), whereas the fenced configuration maintained comparatively stable flow up to 12° and exhibited pronounced instability primarily at 15°–17°. The results demonstrate that a 60° forward wingtip fence enhances upper-surface flow stability and postpones separation onset at low Reynolds numbers, providing experimental guidance for compact wingtip-device optimization.
References
[1] E. Turanoguz and N. Alemdaroglu, “Design of a medium range tactical UAV and improvement of its performance by using winglets,” 2015 International Conference on Unmanned Aircraft Systems, ICUAS 2015, no. June 2015, pp. 1074–1083, 2015.
[2] S. G. Kontogiannis, D. E. Mazarakos, and V. Kostopoulos, “ATLAS IV wing aerodynamic design: From conceptual approach to detailed optimization,” Aerospace Science and Technology, vol. 56, pp. 135–147, 2016.
[3] N. Mulvany, L. Chen, J. Tu, and B. Anderson, “Steady-State Evaluation of Two-Equation RANS (Reynolds-Averaged Navier-Stokes) Turbulence Models for High-Reynolds Number Hydrodynamic Flow Simulations,” Department of Defense, Australian Government, pp. 1–54, 2004.
[4] E. Turanoguz and N. Alemdaroglu, “Design of a medium range tactical UAV and improvement of its performance by using winglets,” 2015 International Conference on Unmanned Aircraft Systems, ICUAS 2015, no. June 2015, pp. 1074–1083, 2015.
[5] S. P. Setyo Hariyadi, Sutardi, W. A. Widodo, and M. A. Mustaghfirin, “Aerodynamics analysis of the wingtip fence effect on UAV wing,” International Review of Mechanical Engineering, vol. 12, no. 10, 2018.
[6] S. P. Setyo Hariyadi, Sutardi, and W. A. Widodo, “Numerical study of flow characteristics around wing airfoil Eppler 562 with variations of rearward wingtip fence,” in AIP Conference Proceedings, vol. 1983, 2018.
[7] S. S. P. Hariyadi, Sutardi, and W. A. Widodo, “Drag reduction analysis of wing airfoil E562 with forward wingtip fence at cant angle variations of 75°and 90°,” in AIP Conference Proceedings, vol. 2001, 2018.
[8] G. K. Ananda, P. P. Sukumar, and M. S. Selig, “Measured aerodynamic characteristics of wings at low Reynolds numbers,” Aerospace Science and Technology, vol. 42, pp. 392–406, 2015.
[9] A. Choudhry, R. Leknys, M. Arjomandi, and R. Kelso, “An insight into the dynamic stall lift characteristics,” Experimental Thermal and Fluid Science, vol. 58, pp. 188–208, 2014.
[10] R. R. Leknys, M. Arjomandi, R. M. Kelso, and C. Birzer, “Dynamic- and post-stall characteristics of pitching airfoils at extreme conditions,” Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, vol. 232, no. 6, pp. 1171–1185, 2018.
[11] K. L. Tomek, A. H. Ullah, C. Fabijanic, and J. Estevadeordal, “Experimental investigation of dynamic stall on pitching swept finiteaspect-ratio wings,” AIAA Scitech 2020 Forum, vol. 1 PartF, no. January, pp. 1–35, 2020.
[12] P. Wang and Z. Shi, “Study of deep-stall characteristics and longitudinal special phenomena of T-tail aircraft,” 2010 IEEE International Conference on Mechatronics and Automation, ICMA 2010, pp. 59–64, 2010.
[13] R. T. Taylor and E. J. Ray, “A Systematic Study of the Factors Contributing to Post-Stall Longitudinal Stability of T-Tail Transport Configurations,” in AIAA Aircraft Design and Technology Meeting, pp. 15–18, 1965.
[14] J. Winslow, H. Otsuka, B. Govindarajan, and I. Chopra, “Basic understanding of airfoil characteristics at low Reynolds numbers (104– 105),” Journal of Aircraft, vol. 55, no. 3, pp. 1050–1061, 2018.
[15] Huang S, Hu Y, Wang Y. Research on aerodynamic performance of a novel dolphin head-shaped bionic airfoil. Energy 2021;214. https://doi.org/10.1016/j. energy.2020.118179.
[16] Zhao M, Cao H, Zhang M, Liao C, Zhou T. Optimal design of aeroacoustic airfoils with owl-inspired trailing-edge serrations. Bioinspir Biomim 2021;16:56004. https://doi.org/10.1088/1748-3190/ac03bd.
[17] Fan M, Dong X, Li Z, Sun Z, Feng L. Numerical and experimental study on flow separation control of airfoils with various leading-edge tubercles. Ocean Eng 2022;252:111046. https://doi.org/10.1016/j.oceaneng.2022.111046.
[18] T. Rimadhani Hermawati, S. Hariyadi Suranto, and N. Pambudiyatno, “3 Dimensional Aerodynamic Analysis of Additional Slat and Slot on Airfoil Naca 23018 Using Computational Fluid Dynamic Method”, JSTN, vol. 2, no. 2, pp. 26–36, May 2025.
[19] Zhang Y, Chen H, Fu S, Dong W. Numerical study of an airfoil with riblets installed based on large eddy simulation. Aerosp Sci Technol 2018;78:661–70. https://doi.org/10.1016/j.ast.2018.05.013.
[20] Sanei M, Razaghi R. Numerical investigation of three turbulence simulation models for S809 wind turbine airfoil. Proc Inst Mech Eng Part A J Power Energy 2018;232:1037–48. https://doi.org/10.1177/0957650918767301.
[21] S. N. Trysnavirensa, S. H. S. Putro, and N. Pambudiyatno, “The Effect of Triangular Vortex Generator Straight Arrangements on the NACA 0012 Airfoil Using a Smoke Generator”, JSTN, vol. 2, no. 1, pp. 38–52, Feb. 2025.
[22] Mansi A, Aydin D. The impact of trailing edge flap on the aerodynamic performance of small-scale horizontal axis wind turbine. Energy Convers Manag 2022;256:115396. https://doi.org/10.1016/j.enconman.2022.115396.
[23] Reddy SR, Dulikravich GS, Abdoli A, Multi-winglets SH. Multi-objective optimization of aerodynamic shapes. In: 53rd AIAA Aerosp Sci Meet; 2015. https://doi.org/10.2514/6.2015-1489.
[24] Anitha D, Shamili GK, Ravi Kumar P, Sabari VR. Air foil Shape Optimization Using Cfd and Parametrization Methods. Mater Today: Proc 2018;5:5364–73. https://doi.org/10.1016/j.matpr.2017.12.122.
[25] A. Faadihillah, S. Hariyadi Suranto Putro, and A. Wulansari, “Aerodynamic Performance Optimization on NACA 2412 Airfoil Flap With The Addition of Riblets”, JSTN, vol. 2, no. 3, pp. 17–34, Aug. 2025.
[26] Li J, He S, Martins JRRA. Data-driven constraint approach to ensure low-speed performance in transonic aerodynamic shape optimization. Aerosp Sci Technol 2019;92:536–50. https://doi.org/10.1016/j.ast.2019.06.008.
[27] Li X, Zhang L, Song J, Bian F, Yang K. Airfoil design for large horizontal axis wind turbines in low wind speed regions. Renew Energy 2020;145:2345–57. https:// doi.org/10.1016/j.renene.2019.07.163.
[28] Wei X, Wang X, Chen S. Research on parameterization and optimization procedure of low-Reynolds-number airfoils based on genetic algorithm and Bezier curve. Adv Eng Softw 2020;149:102864. https://doi.org/10.1016/j. advengsoft.2020.102864.
