Experiments in Fluids

, 60:16 | Cite as

Wake/shear layer interaction for low-Reynolds-number flow over multi-element airfoil

  • Jiangsheng Wang
  • Jinjun WangEmail author
  • Kyung Chun Kim
Research Article


Time-resolved particle image velocimetry (TR-PIV) and hydrogen bubble visualization are employed to study the effects of Reynolds number on the wake/shear layer interactions over multi-element airfoil (30P30N). The Reynolds number based on the stowed chord length (Rec) ranges from 9.3 × 103 to 3.05 × 104. According to the variation of dominated flow structures, a critical Rec interval from 1.27 × 104 to 1.38 × 104 is found, which is novel for the low-Reynolds-number flow over multi-element airfoil. The slat wakes can be divided into two types by this critical interval. When Rec is smaller than this critical interval, no roll-up occurs to the shear layer of slat cusp. Görtler vortices generated by a virtual curved wall dominate the slat wake. When Rec is larger than this critical interval, roll-ups occur to the shear layer of slat cusp, which is similar to the cases at high Reynolds number (Rec ~ 106). These roll-ups and their evolution result in the co-existence of spanwise vortices and streamwise vortices in the slat wake. Different kinds of slat wake result in different kinds of wake/shear layer interactions above the main element. The flow physics behind these complex interactions, especially the novel flow structures and their evolution, is analyzed in detail to contribute to the fundamental research of wake/shear layer interactions. When Görtler vortices dominate the slat wake, they could trigger streaky structures within the leading-edge separated shear layer of the main element. When spanwise vortices and streamwise vortices co-exist in the slat wake, novel spanwise “double secondary vortices” are triggered above the main element by the spanwise vortices of slat cusp shear layer.

Graphical abstract



This work is supported by the National Natural Science Foundation of China (11761131009, 11721202).


  1. Ashton N, West A, Mendonça F (2016) Flow dynamics past a 30P30N three-element airfoil using improved delayed detached-eddy simulation. AIAA J 29:3657–3667CrossRefGoogle Scholar
  2. Balzer W, Fasel HF (2016) Numerical investigation of the role of free-stream turbulence in boundary-layer separation. J Fluid Mech 801:289–321MathSciNetCrossRefGoogle Scholar
  3. Boutilier MS, Yarusevych S (2012a) Effects of end plates and blockage on low-reynolds-number flows over airfoils. AIAA J 50:1547–1559CrossRefGoogle Scholar
  4. Boutilier MSH, Yarusevych S (2012b) Separated shear layer transition over an airfoil at a low Reynolds number. Phys Fluids 24:084105CrossRefGoogle Scholar
  5. Burgmann S, Schröder W (2008) Investigation of the vortex induced unsteadiness of a separation bubble via time-resolved and scanning PIV measurements. Exp Fluids 45:675–691CrossRefGoogle Scholar
  6. Carmichael B (1981) Low Reynolds number airfoil survey, vol 1. NASA Technical Report, NASA-CR- 165803Google Scholar
  7. Cenedese A, Del Prete Z, Miozzi M, Querzoli G (2005) A laboratory investigation of the flow in the left ventricle of a human heart with prosthetic tilting-disk valves. Exp Fluids 39:322–335CrossRefGoogle Scholar
  8. Champagnat F, Plyer A, Le Besnerais G, Leclaire B, Davoust S, Le Sant Y (2011) Fast and accurate PIV computation using highly parallel iterative correlation maximization. Exp Fluids 50:1169–1182CrossRefGoogle Scholar
  9. Choudhari MM, Khorrami MR (2007) Effect of three-dimensional shear-layer structures on slat cove unsteadiness. AIAA J 45:2174–2186CrossRefGoogle Scholar
  10. Choudhari M, Lockard DP Assessment of slat noise predictions for 30P30N high-lift configuration from BANC-III workshop. In: 21st AIAA/CEAS aeroacoustics conference (2015) p 2844Google Scholar
  11. Choudhari MM, Yamamoto K (2012) Integrating CFD, CAA, and experiments towards benchmark datasets for airframe noise problems, NASA Conference Paper NF-1676L-14832Google Scholar
  12. Coull JD, Hodson HP (2011) Unsteady boundary-layer transition in low-pressure turbines. J Fluid Mech 681:370–410CrossRefGoogle Scholar
  13. Deck S, Laraufie R (2013) Numerical investigation of the flow dynamics past a three-element aerofoil. J Fluid Mech 732:401–444CrossRefGoogle Scholar
  14. Deng S-C, Pan C, Wang J-J, Rinoshika A (2017) POD analysis of the instability mode of a low-speed streak in a laminar boundary layer. Acta Mech Sin 33:981–991CrossRefGoogle Scholar
  15. Dobrzynski W (2010) Almost 40 years of airframe noise research: what did we achieve? J Aircr 47:353–367CrossRefGoogle Scholar
  16. Gaster M (1969) The structure and behaviour of laminar separation bubbles. H.M. Stationery Office, pp 1–31Google Scholar
  17. Hain R, Kähler C, Radespiel R (2009) Dynamics of laminar separation bubbles at low-Reynolds-number aerofoils. J Fluid Mech 630:129–153CrossRefGoogle Scholar
  18. Haines A (1994) Scale Effects on Aircraft and Weapon Aerodynamics (Les Effets d’Echelle et l’Aerodynamique des Aeronefs et des Systemes d’Armes). DTIC DocumentGoogle Scholar
  19. Hansen H, Thiede P, Moens F, Rudnik R, Quest J (2004) Overview about the European high lift research programme EUROLIFT AIAA Paper 767:2004Google Scholar
  20. He G, Wang J, Pan C (2013) Initial growth of a disturbance in a boundary layer influenced by a circular cylinder wake. J Fluid Mech 718:116–130CrossRefGoogle Scholar
  21. He G-S, Pan C, Feng L-H, Gao Q, Wang J-J (2016) Evolution of Lagrangian coherent structures in a cylinder-wake disturbed flat plate boundary layer. J Fluid Mech 792:274–306MathSciNetCrossRefGoogle Scholar
  22. Istvan MS, Yarusevych S (2018) Effects of free-stream turbulence intensity on transition in a laminar separation bubble formed over an airfoil. Exp Fluids 59:52CrossRefGoogle Scholar
  23. Jenkins LN, Khorrami MR, Choudhari M (2004) Characterization of unsteady flow structures near leading-edge slat: Part I. PIV measurements AIAA paper 2801:2004Google Scholar
  24. Jones L, Sandberg R, Sandham N (2008) Direct numerical simulations of forced and unforced separation bubbles on an airfoil at incidence. J Fluid Mech 602:175–207CrossRefGoogle Scholar
  25. Kurelek JW, Lambert AR, Yarusevych S (2016) Coherent structures in the transition process of a laminar separation bubble. AIAA J 54(8):2295–2309CrossRefGoogle Scholar
  26. Kyriakides NK, Kastrinakis EG, Nychas SG, Goulas A (1999) Aspects of flow structure during a cylinder wake-induced laminar/turbulent transition. AIAA J 37:1197–1205CrossRefGoogle Scholar
  27. Lang M, Rist U, Wagner S (2004) Investigations on controlled transition development in a laminar separation bubble by means of LDA and PIV. Exp Fluids 36:43–52CrossRefGoogle Scholar
  28. Lengani D, Simoni D, Ubaldi M, Zunino P (2014) POD analysis of the unsteady behavior of a laminar separation bubble Experimental. Thermal Fluid Sci 58:70–79CrossRefGoogle Scholar
  29. Lissaman P (1983) Low-Reynolds-number airfoils. Annu Rev Fluid Mech 15:223–239CrossRefGoogle Scholar
  30. Ma L, Feng L, Pan C, Gao Q, Wang J (2015) Fourier mode decomposition of PIV data Science, China. Technol Sci 58:1935–1948Google Scholar
  31. Makiya S, Inasawa A, Asai M (2010) Vortex shedding and noise radiation from a slat trailing edge. AIAA J 48:502–509CrossRefGoogle Scholar
  32. Mandal AC, Dey J (2011) An experimental study of boundary layer transition induced by a cylinder wake. J Fluid Mech 684:60–84CrossRefGoogle Scholar
  33. Marxen O, Henningson DS (2011) The effect of small-amplitude convective disturbances on the size and bursting of a laminar separation bubble. J Fluid Mech 671:1–33CrossRefGoogle Scholar
  34. Marxen O, Lang M, Rist U, Levin O, Henningson DS (2009) Mechanisms for spatial steady three-dimensional disturbance growth in a non-parallel and separating boundary layer. J Fluid Mech 634:165–189CrossRefGoogle Scholar
  35. Marxen O, Lang M, Rist U (2013) Vortex formation and vortex breakup in a laminar separation bubble. J Fluid Mech 728:58–90MathSciNetCrossRefGoogle Scholar
  36. McAuliffe BR, Yaras MI (2009) Transition mechanisms in separation bubbles under low- and elevated-freestream turbulence. J Turbomach 132:011004–011004CrossRefGoogle Scholar
  37. Mueller TJ, DeLaurier JD (2003) Aerodynamics of small vehicles. Annu Rev Fluid Mech 35:89–111CrossRefGoogle Scholar
  38. Ovchinnikov V, Piomelli U, Choudhari MM (2006) Numerical simulations of boundary-layer transition induced by a cylinder wake. J Fluid Mech 547:413–441CrossRefGoogle Scholar
  39. Pagani CC Jr, Souza DS, Medeiros MA (2016) Slat noise: aeroacoustic beamforming in closed-section wind tunnel with numerical comparison. AIAA J 54:2100–2115CrossRefGoogle Scholar
  40. Pan C, Wang JJ, Zhang PF, Feng LH (2008) Coherent structures in bypass transition induced by a cylinder wake. J Fluid Mech 603:367–389CrossRefGoogle Scholar
  41. Pan C, Wang H, Wang J (2013) Phase identification of quasi-periodic flow measured by particle image velocimetry with a low sampling rate. Meas Sci Technol 24:055305CrossRefGoogle Scholar
  42. Pan C, Xue D, Xu Y, Wang J, Wei R (2015) Evaluating the accuracy performance of Lucas–Kanade algorithm in the circumstance of PIV application Science China. Phys Mech Astron 58:1–16CrossRefGoogle Scholar
  43. Paschal K, Jenkins L, Yao C (2000) Unsteady slat-wake characteristics of a high-lift configuration. AIAA paper 139:2000Google Scholar
  44. Pascioni KA, Cattafesta LN (2018) Unsteady characteristics of a slat-cove flow field. Phys Rev Fluids 3:034607CrossRefGoogle Scholar
  45. Pascioni KA, Cattafesta LN, Choudhari MM (2014) An Experimental investigation of the 30P30N multi-element high-lift airfoil. 20th AIAA/CEAS Aeroacoustics Conference, Atlanta, Georgia, 16–20 June 2014Google Scholar
  46. Schrader L-U, Brandt L, Mavriplis C, Henningson DS (2010) Receptivity to free-stream vorticity of flow past a flat plate with elliptic leading edge. J Fluid Mech 653:245–271CrossRefGoogle Scholar
  47. Simoni D, Ubaldi M, Zunino P, Lengani D, Bertini F (2012) An experimental investigation of the separated-flow transition under high-lift turbine blade pressure gradients flow. Turbul Combust 88:45–62CrossRefGoogle Scholar
  48. Simoni D, Lengani D, Ubaldi M, Zunino P, Dellacasagrande M (2017) Inspection of the dynamic properties of laminar separation bubbles: free-stream turbulence intensity effects for different Reynolds numbers. Exp Fluids 58:66CrossRefGoogle Scholar
  49. Souza DS, Rodríguez D, Simões LGC, Medeiros MAF (2015) Effect of an excrescence in the slat cove: flow-field, acoustic radiation and coherent structures. Aerosp Sci Technol 44:108–115CrossRefGoogle Scholar
  50. Squire L (1989) Interactions between wakes and boundary-layers. Prog Aerosp Sci 26:261–288CrossRefGoogle Scholar
  51. Van Dam C (2002) The aerodynamic design of multi-element high-lift systems for transport airplanes. Prog Aerosp Sci 38:101–144CrossRefGoogle Scholar
  52. Wang J-S, Feng L-H, Wang J-j, Li T (2018) Görtler vortices in low-Reynolds-number flow over multi-element airfoil. J Fluid Mech 835:898–935CrossRefGoogle Scholar
  53. Welch P (1967) The use of fast Fourier transform for the estimation of power spectra: a method based on time averaging over short, modified periodograms. IEEE Trans Audio Electroacoust 15:70–73CrossRefGoogle Scholar
  54. Winslow J, Otsuka H, Govindarajan B, Chopra I (2017) Basic Understanding of airfoil characteristics at low Reynolds numbers (10 4–10 5) J Aircr 55:1–12Google Scholar
  55. Ying SX, Spaid FW, McGinley CB, Rumsey CL (1999) Investigation of confluent boundary layers in high-lift flows. J Aircr 36:550–562CrossRefGoogle Scholar
  56. Zhu H-Y, Wang C-Y, Wang H-P, Wang J-J (2017) Tomographic PIV investigation on 3D wake structures for flow over a wall-mounted short cylinder. J Fluid Mech 831:743–778CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Key Laboratory of Fluid Mechanics (Beijing University of Aeronautics and Astronautics)Ministry of EducationBeijingChina
  2. 2.School of Mechanical EngineeringPusan National UniversityBusanRepublic of Korea

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