Flow properties of an Ahmed Body with different passive flow control methods

Abstract

A numerical simulation by utilizing the FloEFD software was carried out in order to investigate the flow topology formed on slant surface and wake region of an Ahmed Body with and without passive flow control techniques. The effects of those flow controllers on flow at the slant surface and wake region by influencing the flow topology as well as aerodynamic drag coefficient examined carefully. The numerical findings clearly revealed that the best performance in terms of providing the drag reduction obtained when sphere and hemispherical shape flow control techniques were applied at the rear part of slant surface of Ahmed Body. Sphere and hemispherical shape flow controllers positioned at the rear part of slant surface led to have drag reduction of 6% and 7%, respectively. Besides, the results of current study compared with the results obtained from published studies in the literature. It was clearly observed that they are consistent with each other even though they were found by different software.

Keywords

• Ahmed body
• Vehicle aerodynamics
• Passive flow control
• Drag reduction
• FloEFD

Kaynakça

1. [1] Ahmed, S. R., Ramm, G., Faltin, G. Some salient features of the time-averaged ground vehicle wake. SAE transactions. 1984; 473-503.
2. [2] Morel, T. The effect of base slant on the flow pattern and drag of three-dimensional bodies with blunt ends. In Aerodynamic drag mechanisms of bluff bodies and road vehicles, 1978; 191-226.
3. [3] Zigunov, F., Sellappan, P., Alvi, F. Reynolds number and slant angle effects on the flow over a slanted cylinder afterbody. Journal of Fluid Mechanics. 2020; 893: A11.
4. [4] Zhang, B. F., Zhou, Y., To, S. Unsteady flow structures around a high-drag Ahmed body. Journal of Fluid Mechanics. 2015; 777: 291-326.
5. [5] Grandemange, M., Gohlke, M., Cadot, O. Turbulent wake past a three-dimensional blunt body. Part 1. Global modes and bi-stability. Journal of Fluid Mechanics. 2013; 722: 51-84.
6. [6] Genç, M. S., Koca, K., Demir, H., Açıkel, H. H. Traditional and new types of passive flow control techniques to pave the way for high maneuverability and low structural weight for UAVs and MAVs. Autonomous Vehicles. 2020; 131-160.
7. [7] Bellman, M., Agarwal, R., Naber, J., Chusak, L. Reducing energy consumption of ground vehicles by active flow control. In Energy Sustainability. 2010; 785-793.
8. [8] Kourta, A., Leclerc, C. Characterization of synthetic jet actuation with application to Ahmed body wake. Sensors and Actuators A: Physical. 2013; 192: 13-26.

9. [9] Joseph, P., Amandolese, X., Edouard, C., Aider, J. L. Flow control using MEMS pulsed micro-jets on the Ahmed body. Experiments in fluids. 2013; 54: 1-12.
10. [10] Zhang, B. F., Liu, K., Zhou, Y., To, S., Tu, J. Y. Active drag reduction of a high-drag Ahmed body based on steady blowing. Journal of Fluid Mechanics. 2018; 856: 351-396.
11. [11] Brunn, A., Nitsche, W. Active control of turbulent separated flows over slanted surfaces. International Journal of Heat and Fluid Flow. 2006; 27(5): 748-755.
12. [12] Fourrié, G., Keirsbulck, L., Labraga, L., Gilliéron, P. Bluff-body drag reduction using a deflector. Experiments in Fluids. 2011; 50: 385-395.
13. [13] Mariotti, A., Buresti, G., Gaggini, G., Salvetti, M. V. (2017). Separation control and drag reduction for boat-tailed axisymmetric bodies through contoured transverse grooves. Journal of Fluid Mechanics. 2017; 832: 514-549.
14. [14] Aider, J. L., Beaudoin, J. F., Wesfreid, J. E. Drag and lift reduction of a 3D bluff-body using active vortex generators. Experiments in fluids. 2010; 48: 771-789.
15. [15] Rossitto, G., Sicot, C., Ferrand, V., Borée, J., Harambat, F. Influence of afterbody rounding on the pressure distribution over a fastback vehicle. Experiments in Fluids. 2016; 57: 1-12.
16. [16] Evrard, A., Cadot, O., Herbert, V., Ricot, D., Vigneron, R., Délery, J. Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity. Journal of Fluids and Structures. 2016; 61: 99-114.
17. [17] Minguez, M., Pasquetti, R., Serre, E. High-order LES of the flow over a simplified car model: On the influence of the Reynolds number. European Journal of Computational Mechanics/Revue Européenne de Mécanique Numérique. 2009; 18(7-8): 627-646.
18. [18] Kang, N., Essel, E. E., Roussinova, V., Balachandar, R. Effects of approach flow conditions on the unsteady three-dimensional wake structure of a square-back Ahmed body. Physical Review Fluids. 2021; 6(3): 034613.
19. [19] Tunay, T., Firat, E., Sahin, B. Experimental investigation of the flow around a simplified ground vehicle under effects of the steady crosswind. International Journal of Heat and Fluid Flow. 2018; 71: 137-152.
20. [20] Venning, J., McQueen, T., Jacono, D. L., Burton, D., Thompson, M., Sheridan, J. Aspect ratio and the dynamic wake of the Ahmed body. Experimental Thermal and Fluid Science. 2022; 130: 110457.
21. [21] Essel, E., Das, S., Balachandar, R. Effects of rear angle on the turbulent wake flow between two in-line Ahmed bodies. Atmosphere. 2020; 11(4): 328.
22. [22] Tunay, T., Yaniktepe, B., Sahin, B. Computational and experimental investigations of the vortical flow structures in the near wake region downstream of the Ahmed vehicle model. Journal of Wind Engineering and Industrial Aerodynamics. 2016; 159: 48-64.
23. [23] Bruneau, C. H., Mortazavi, I., Gilliéron, P. Passive control around the two-dimensional square back Ahmed body using porous devices. Journal of Fluid Engineering. 2008; 130: 1-12.
24. [24] Tunay, T., Sahin, B., Akilli, H. Experimental and numerical studies of the flow around the Ahmed body. Wind and Structures. 2013; 17(5): 515-535.
25. [25] Podvin, B., Pellerin, S., Fraigneau, Y., Evrard, A., Cadot, O. Proper orthogonal decomposition analysis and modelling of the wake deviation behind a squareback Ahmed body. Physical Review Fluids. 2020; 5(6): 064612.
26. [26] Cadot, O., Evrard, A., Pastur, L. Imperfect supercritical bifurcation in a three-dimensional turbulent wake. Physical Review E. 2015; 91(6): 063005.
27. [27] Tunay, T., Sahin, B., Ozbolat, V. Effects of rear slant angles on the flow characteristics of Ahmed body. Experimental Thermal and Fluid Science. 2014; 57: 165-176.
28. [28] Grandemange, M., Cadot, O., Gohlke, M. Reflectional symmetry breaking of the separated flow over three-dimensional bluff bodies. Physical review E. 2012; 86(3): 035302.
29. [29] Demir, H., Özden, M., Genç, M. S., Çağdaş, M. Numerical investigation of flow on NACA4412 aerofoil with different aspect ratios. In EPJ Web of Conferences. 2016; 114: 02016.
30. [30] Özden, M., Genç, M. S., Koca, K. Investigation of the effect of hidden vortex generator-flap integrated mechanism revealed in low velocities on wind turbine blade flow. Energy Conversion and Management. 2023; 287: 117107.
31. [31] Özden, M., Koca, K. Öndeki Aracın Akışına Maruz Kalan Otobüsün Üzerinde Oluşan Aerodinamik Etkinin Sayısal Olarak İncelenmesi. Erciyes Üniversitesi Fen Bilimleri Enstitüsü Fen Bilimleri Dergisi. 2023; 39(1): 116-125.
32. [32] Özden, M., Genç, M. S., Koca, K. Passive Flow Control Application Using Single and Double Vortex Generator on S809 Wind Turbine Airfoil. Energies. 2023; 16(14): 5339.
33. [33] Genc, M. S., Koca, K., Acikel, H. H. Investigation of pre-stall flow control on wind turbine blade airfoil using roughness element. Energy. 2019; 176: 320-334.
34. [34] Pujals, G., Depardon, S., Cossu, C. Drag reduction of a 3D bluff body using coherent streamwise streaks. Experiments in fluids. 2010; 49: 1085-1094.
35. [35] User guide of FloEFD, Siemens Digital Industries Software, SIEMENS, https://plm.sw.siemens.com/en-US/simcenter/fluids-thermal-simulation/floefd/
36. [36] Karasu, İ., Özden, M., Genç, M. S. Performance assessment of transition models for three-dimensional flow over NACA4412 wings at low Reynolds numbers. Journal of Fluids Engineering. 2018; 140(12): 121102.
37. [37] Koca, K., Genc, M. S., Veerasamy, D., Özden, M. Experimental flow control investigation over suction surface of turbine blade with local surface passive oscillation. Ocean Engineering. 2022; 266: 113024.
38. [38] Genç, M. S., Özkan, G., Özden, M., Kırış, M. S., Yıldız, R. Interaction of tip vortex and laminar separation bubble over wings with different aspect ratios under low Reynolds numbers. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science. 2018; 232(22): 4019-4037.
39. [39] Koca, K., Genç, M. S., Ertürk, S. Impact of local flexible membrane on power efficiency stability at wind turbine blade. Renewable Energy. 2022; 197: 1163-1173.
40. [40] H Demir, MS Genç, An experimental investigation of laminar separation bubble formation on flexible membrane wing, European Journal of Mechanics-B/Fluids. 2017; 65: 326-338.
41. [41] Genç, M. S., Koca, K., Açıkel, H. H., Özkan, G., Kırış, M. S., Yıldız, R. Flow characteristics over NACA4412 airfoil at low Reynolds number. In EPJ web of conferences. 2016; 114: 02029
42. [42] Karasu, I., Genc, M. S., Acikel, H. H., Akpolat, M. T. An experimental study on laminar separation bubble and transition over an aerofoil at low Reynolds number. In 30th AIAA applied aerodynamics conference. 2012; 3030.
43. [43] Koca, K., Genç, M. S., Özkan, R. Mapping of laminar separation bubble and bubble-induced vibrations over a turbine blade at low Reynolds numbers. Ocean Engineering. 2021; 239: 109867.
44. [44] Koca, K., Genç, M. S., Açıkel, H. H., Çağdaş, M., Bodur, T. M. Identification of flow phenomena over NACA 4412 wind turbine airfoil at low Reynolds numbers and role of laminar separation bubble on flow evolution. Energy. 2018; 144: 750-764.
45. [45] Koca, K., Genç, M.S., Açıkel, H.H. Rüzgar Türbini Kanadı Üzerindeki Yüzey Pürüzlülüğü Etkisinin Deneysel İncelenmesi. Çukurova Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi. 2016; 31(ÖS2): 127-134.
46. [46] Kamacı, C., Kaya, K. Numerical Investigation of Aerodynamic Properties of Ahmed Body for Different Rear Slanted Surface Configurations. Avrupa Bilim ve Teknoloji Dergisi. 2021; 28: 469-475.
47. [47] Yang, X., Hu, Y., Gong, Z., Jian, J., Liu, Z. Numerical study of combined drag reduction bases on vortex generators and riblets for the ahmed body using IDDES methodology. Journal of Applied Fluid Mechanics. 2021; 15(1): 193-207.