Effects of Different Shaped Cavities and Bumps on Flow Structure and Wing Performance

Document Type : Regular Article


1 Faculty of Mechanical Engineering, Department of Mechanics, University of Sciences and Technology of Oran Mohamed Boudiaf, BP. 1505 Oran El M'Naouer, 31000 Oran, Algeria

2 Icube Laboratory, Department of Mechanics, National Institute of Applied Sciences, 67084, Strasbourg, France



The stall of an aircraft is one of the most dangerous phenomena in the aviation world, resulting in a sudden loss of lift because of boundary layer separation. This work aims to delay separation and to improve wing aerodynamic performances by introducing bumps and cavities on the upper surfaces of the wing. A numerical study on the effects of both cavities and bumps on flow structures and wing aerodynamics of NACA 0012 profile is conducted. The CFX code has been used to perform calculations of steady and uncompressible Reynolds Averaged Naviers-Stokes equations. The airfoil has been exposed to a free stream velocity of 5.616 m/s and chord based Reynolds number of 3.6 x 105 (chord length). A series of test on unmodified airfoil has been carried out for various turbulence models at angles of attack ranging from 0° to 15°. Then, the two-equation k-ω SST (Shear Stress Transport) has been retained for the further cases. Different configurations obtained through a modification of cavities and bumps shape, dimension, and position on the airfoil chord are investigated. Both the shapes considered are semi-spherical and semi-cylindrical, placed at two positions on the airfoil chord. The first location is in suction pick at X/C= 0.3 and the second one is at 0.7. Results show that the application of bumps delays the boundary layer separation and increase drag coefficient. A slight enhancement in lift and drag is observed at angle of attack of 15° for the cases where the cavities are placed at 0.7 m from the leading edge. In addition, calculations show that the stability of the vortex formed inside the cavities depends strongly on their shape and the cylindrical one has better performances.


Avelar, A. C., L. A. Santos, O. A. F. Mello and J. Pagani (2006). A PIV Study of the Flow around a NACA 0012 Airfoil in a Subsonic Wind Tunnel. 25th AIAA Aerodynamic Measurement Technology and Ground Testing Conference, San Francisco, California, 3143.##
Barth, T. J. and D. C. Jesperson (1989). The Design and Application of Upwind Schemes on Unstructured Meshes. 27th Aerospace Sciences Meeting, Reno, Nevada, 0366.##
Booma, P. and D. A. Shah (2016). Computational Analysis of Cavity Effect Over Aircraft Wing. International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering 10(4), 774-777.##
Bres, G. and T. Colonius (2008). Three-Dimensional Instabilities in Compressible Flow over Open Cavities. Journal of  Fluid Mechanics 599(Mar.), 309-339.##
Bunyakin, A. V., S. I .Chernyshenko and G. Y. Stepanov (1998). High-Reynolds-Number Batchelor-Model Asymptotics of a Flow Past an Aerofoil with a Vortex Trapped in a Cavity. Journal of Fluid Mechanics 358(1), 283-297.##
Chernyshenko, S. I., B. Galletti, A. Iollo and L. Zannetti (2003). Trapped Vortices and a Favourable Pressure Gradient. Journal of Fluid Mechanics 482(May.), 235-255.##
Eleni, D. C., T. I. Athanasios and M. P. Dionissios (2012). Evaluation of the Turbulence Models for the Simulation of the Flow over a National Advisory Committee for Aeronautics (NACA) 0012 Airfoil. Journal of Mechanical Engineering Research 4(3),100-111.##
Fatehi, M., M. Nili-Ahmadabadi, O. Nematollahi,  A. Minaean and K. C. Kim (2018). Aerodynamic Performance Improvement of Wind Turbine Blade by Cavity Shape Optimization. Renewable Energy 132 (Mar.), 773-785##
Gregorio, F. D. and G. Fraioli (2008). Flow Control on a High Thickness Airfoil by a Trapped Vortex Cavity. 14th Int Symp on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal, 1363.##
Isaev, S. A., P. A. Baranov, N. I. Vatin, Y. V. Zhukova and A. G. Sudakov (2014). Suppression of the Karman Vortex Street and Reduction in the Frontal Drag of a Circular Cylinder with Two Vortex Cells. Technical Physics Letters 40(8), 653-656.##
Janardhanan, S. and P. Thaliyakkattil (2015). Numerical Study on Aerofoil Stall.  International Conference on Emerging Research in Engineering Science and Technology, Coimbatore, India.##
Katz, J. and A. Polotkin (1991). Low-Speed Aerodynamics. McGraw-Hill Series in  Aeronautical and Aerospace Engineering, New York, 632.##
Kruppa, E. W. (1977). Wind Tunnel Investigation of the Kasper Vortex Concept. 13th annual meeting and technical display incorporating the forum on the future of air transportation, Washington, DC, (Jan.), 10–13.##
Moran, J. (1984). Theoritical and Computational Aerodynamics. John Wiley and Sons, New York, 464.##
Narayana, P. A. A., K. A. Rasya and S. S. Prasad (2018). Effect of Outward and Inward Dimple Located on Different Positions of Aerofoil Section at a Typical Low Reynolds Number. International Journal of Engineering and Technology 7 (4.25), 29-34.##
Prasath, M. S. and S. I. Angelin (2017). Effect of Dimples on Aircraft Wing. GRD Journals- Global Research and Development Journal for Engineering 2(5), 234–242.##
Roy, J. F. (1988). Fluides parfaits incompressibles. Edition Marketing, Ellipses, France.##
Savitsky, A. I., L. N. Schukin, V. G. Karelin, R. M. Pushkin, A. M. Mass, A. P. Shibanov, I. L. Schukin and S. V. Fischenko (1995). Method for control of the boundary layer on the aerodynamic surface of an aircraft, and the aircraft provided with the boundary layer control system. United States Patent, 5417391.##
Sheldahl, R. E. and P. C. Klimas (1981). Aerodynamic Characteristics of Seven Symmetrical Airfoil Sections through 180-Degree Angle of Attack for Use in Aerodynamic Analysis of Vertical Axis Wind Turbines. Sandia Natl. Labs., Albuquerque, NM 80-2114, 19.##
Sørensen, N. (2009). Airfoil Computations Using the γ-Reθ Model. Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi. Denmark. Forskningscenter Risoe. Risoe-R, 1693(EN).##
Sowmyashree, Y., D. I. P. Aishwarya, S. Spurthy, R. Sah, B. V. Pratik, H. V. Srikanth and R. Suthan (2020). Study on Effect of Semi-Circular Dimple on Aerodynamic Characteristics of NACA 2412 Airfoil. AIP Conference Proceedings 2204(Jan.), 030009.##
Srivastav, D. (2012). Flow Control over Airfoils Using Different Shaped Dimples. IPCSIT 33, 92-97.##
Tang, L. (2008).Reynolds-averaged Navier-Stokes simulation of low-Reynolds-number airfoil aerodynamics. Journal of Aircraft 45(3), 848-856##
Volume 15, Issue 6 - Serial Number 67
November and December 2022
Pages 1649-1660
  • Received: 26 January 2022
  • Revised: 26 May 2022
  • Accepted: 18 June 2022
  • First Publish Date: 01 November 2022