Skip to main content
SpringerLink
Log in

Vortex shedding within laminar separation bubbles forming over an airfoil

  • Research Article
  • Published:
Experiments in Fluids Aims and scope Submit manuscript

Abstract

Vortex shedding within laminar separation bubbles forming over the suction side of a NACA 0018 airfoil is studied through a combination of high-speed flow visualization and boundary layer measurements. Wind tunnel experiments are performed at a chord-based Reynolds number of 100,000 and four angles of attack. The high-speed flow visualization is complemented by quantitative velocity and surface pressure measurements. The structures are shown to originate from the natural amplification of small-amplitude disturbances, and the shear layer roll-up is found to occur coherently across the span. However, significant cycle-to-cycle variations are observed in vortex characteristics, including shedding period and roll-up location. The formation of the roll-up vortices precedes the later stages of transition, during which these structures undergo significant deformations and breakdown to smaller scales. During this stage of flow development, vortex merging is also observed. The results provide new insight into the development of coherent structures in separation bubbles and their relation to the overall bubble dynamics and mean bubble topology.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16

Similar content being viewed by others

References

  • Abdalla IE, Yang Z (2004) Numerical study of the instability mechanism in transitional separatingreattaching flow. Int J Heat Fluid Flow 25(4):593–605

    Article  Google Scholar 

  • Alam M, Sandham ND (2000) Direct numerical simulation of ‘short’ laminar separation bubbles with turbulent reattachment. J Fluid Mech 410:1–28

    Article  MATH  Google Scholar 

  • Balzer W, Fasel H (2010) Direct numerical simulation of laminar boundary-layer separation and separation control on the suction side of an airfoil at low Reynolds number conditions. In: 40th Fluid Dyn. Conf. Exhib., American Institute of Aeronautics and Astronautics, Reston, Virigina

  • Batill SM, Mueller TJ (1981) Visualization of transition in the flow over an airfoil using the smoke-wire technique. AIAA J 19(3):340–345

    Article  Google Scholar 

  • Boiko AV, Grek GR, Dovgal AV, Kozlov VV (2002) The origin of turbulence in near-wall flows. Springer, Berlin

    Book  MATH  Google Scholar 

  • Boutilier MSH, Yarusevych S (2012) Effects of end plates and blockage on low-Reynolds-number flows over airfoils. AIAA J 50(7):1547–1559

    Article  Google Scholar 

  • Boutilier MSH, Yarusevych S (2012) Parametric study of separation and transition characteristics over an airfoil at low Reynolds numbers. Exp Fluids 52(6):1491–1506

    Article  Google Scholar 

  • Boutilier MSH, Yarusevych S (2012) Separated shear layer transition over an airfoil at a low Reynolds number. Phys Fluids 24(8):084,105–084,105–23

  • Boutilier MSH, Yarusevych S (2014) Influence of hot-wire probe and traverse on low-Reynolds-number airfoil experiments. AIAA J 52(11):2618–2623

    Article  Google Scholar 

  • Brendel M, Mueller TJ (1988) Boundary-layer measurements on an airfoil at low Reynolds numbers. J Aircr 25(7):612–617

    Article  Google Scholar 

  • Brinkerhoff JR, Yaras MI (2011) Interaction of viscous and inviscid instability modes in separationbubble transition. Phys Fluids 23(12):124, 102

  • 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(4):675–691

    Article  Google Scholar 

  • Burgmann S, Brücker C, Schröder W (2006) Scanning PIV measurements of a laminar separation bubble. Exp Fluids 41(2):319–326

    Article  Google Scholar 

  • Burgmann S, Dannemann J, Schröder W (2008) Time-resolved and volumetric PIV measurements of a transitional separation bubble on an SD7003 airfoil. Exp Fluids 44(4):609–622

    Article  Google Scholar 

  • Carmichael BH (1981) Low Reynolds Number Airfoil Survey. NASA cr 165803

  • Diwan SS, Ramesh ON (2009) On the origin of the inflectional instability of a laminar separation bubble. J Fluid Mech 629:263

    Article  MATH  Google Scholar 

  • Dovgal A, Kozlov V, Michalke A (1994) Laminar boundary layer separation: Instability and associated phenomena. Prog Aerosp Sci 30(1):61–94

    Article  Google Scholar 

  • Gad-El-Hak M (1990) Control of low-speed airfoil aerodynamics. AIAA J 28(9):1537–1552

    Article  Google Scholar 

  • Gaster M (1967) The structure and behaviour of laminar separation bubbles. Reports and memoranda no. 3595, Aeronautical Research Council, London

  • Gerakopulos R, Yarusevych S (2012) Novel time-resolved pressure measurements on an airfoil at a low Reynolds number. AIAA J 50(5):1189–1200

    Article  Google Scholar 

  • Häggmark CP, Hildings C, Henningson DS (2001) A numerical and experimental study of a transitional separation bubble. Aerosp Sci Technol 5(5):317–328

    Article  MATH  Google Scholar 

  • Hain R, Kähler CJ, Radespiel R (2009) Dynamics of laminar separation bubbles at low-Reynolds-number aerofoils. J Fluid Mech 630:129

    Article  MATH  Google Scholar 

  • Gad-el Hak M (2001) Flow control: the future. J Aircr 38(3):402–418

    Article  Google Scholar 

  • Horton H (1968) Laminar separation bubbles in two and three dimensonal incompressible flow. University of London, Ph.d

    Google Scholar 

  • Hudy LM, Naguib A, Humphreys WM (2007) Stochastic estimation of a separated-flow field using wall-pressure-array measurements. Phys Fluids 19(2):024,103

  • Hwang KS, Sung HJ, Hyun JM (2000) Visualizations of large-scale vortices in flow about a blunt-faced flat plate. Exp Fluids 29(2):198–201

    Article  Google Scholar 

  • Jones LE, Sandberg RD, Sandham ND (2008) Direct numerical simulations of forced and unforced separation bubbles on an airfoil at incidence. J Fluid Mech 602:175–207

    Article  MATH  Google Scholar 

  • Kawall JG, Shokr M, Keffer JF (1983) A digital technique for the simultaneous measurement of streamwise and lateral velocities in turbulent flows. J Fluid Mech 133:83–112

    Article  Google Scholar 

  • Kurelek JW, Lambert AR, Yarusevych S (2016) Coherent structures in the transition process of a laminar separation bubble. AIAA J 54(8):2295–2309

    Article  Google Scholar 

  • 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(1):43–52

    Article  Google Scholar 

  • Lissaman PBS (1983) Low-Reynolds-number airfoils. Annu Rev Fluid Mech 15(1):223–239

    Article  MATH  Google Scholar 

  • 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 671:1–33

    Article  MATH  Google Scholar 

  • Marxen O, Rist U (2010) Mean flow deformation in a laminar separation bubble: separation and stability characteristics. J Fluid Mech 660:37–54

    Article  MATH  Google Scholar 

  • Marxen O, Lang M, Rist U (2012) Discrete linear local eigenmodes in a separating laminar boundary layer. J Fluid Mech 711:1–26

    Article  MATH  MathSciNet  Google Scholar 

  • Marxen O, Lang M, Rist U (2013) Vortex formation and vortex breakup in a laminar separation bubble. J Fluid Mech 728:58–90

    Article  MATH  MathSciNet  Google Scholar 

  • McAuliffe BR, Yaras MI (2010) Transition mechanisms in separation bubbles under low- and elevated-freestream turbulence. J Turbomach 132(1):011,004

  • Mueller TJ, Batill SM (1982) Experimental studies of separation on a two dimensional airfoil at low Reynolds numbers. AIAA J 20(4):457–463

    Article  Google Scholar 

  • Mueller TJ, DeLaurier JD (2003) Aerodynamics of small vehicles. Annu Rev Fluid Mech 35(1):89–111

    Article  MATH  Google Scholar 

  • O’Meara MM, Mueller TJ (1987) Laminar separation bubble characteristics on an airfoil at low Reynolds numbers. AIAA J 25(8):1033–1041

    Article  Google Scholar 

  • Pauley L, Moin P, Reynolds W (1990) The structure of two-dimensional separation. J Fluid Mech 220:397–411

    Article  Google Scholar 

  • Rist U, Maucher U, Wagner S (1996) Direct numerical simulation of some fundamental problems related to transition in laminar separation bubbles. In: Proc. ECCOMAS Comput. Fluid Dyn. Conf., pp 319–325

  • Spalart PR, Strelets M (2000) Mechanisms of transition and heat transfer in a separation bubble. J Fluid Mech 403:329–349

    Article  MATH  Google Scholar 

  • Tani I (1964) Low-speed flows involving bubble separations. Prog Aerosp Sci 5:70–103

    Article  Google Scholar 

  • van Ingen J (1956) A suggested semi-empirical method for the calculation of the boundary layer transition region

  • Watanabe Y, Saeki H, Hosking RJ (2005) Three-dimensional vortex structures under breaking waves. J Fluid Mech 545:291–328

    Article  MATH  MathSciNet  Google Scholar 

  • Watmuff JH (1999) Evolution of a wave packet into vortex loops in a laminar separation bubble. J Fluid Mech 397:119–169

    Article  MATH  MathSciNet  Google Scholar 

  • Welch PD (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 AU-15(2):70–73

  • Wolf E, Kähler C, Troolin D, Kykal C, Lai W (2010) Time-resolved volumetric particle tracking velocimetry of large-scale vortex structures from the reattachment region of a laminar separation bubble to the wake. Exp Fluids 50(4):977–988

    Article  Google Scholar 

  • Yang Z, Voke P (2001) Large-eddy simulation of boundary-layer separation and transition at a change of surface curvature. J Fluid Mech 439:305–333

    Article  MATH  Google Scholar 

  • Yarusevych S, Sullivan PE, Kawall JG (2009) On vortex shedding from an airfoil in low-Reynolds-number flows. J Fluid Mech 632:245–271

    Article  MATH  Google Scholar 

  • Yarusevych S, Sullivan PE, Kawall JG (2009) Smoke-wire flow visualization in separated flows at relatively high velocities. AIAA J 47(6):1592–1595

    Article  Google Scholar 

Download references

Acknowledgements

The authors gratefully acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC) and Bombardier Aerospace for funding this work. The authors would also like to thank Andrew Lambert for assisting with flow visualization.

Author information

Authors and Affiliations

  1. University of Waterloo, 200 University Ave. W., Waterloo, ON, N2L 3G1, Canada

    Thomas M. Kirk & Serhiy Yarusevych

Authors
  1. Thomas M. Kirk
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Serhiy Yarusevych
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Serhiy Yarusevych.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kirk, T.M., Yarusevych, S. Vortex shedding within laminar separation bubbles forming over an airfoil. Exp Fluids 58, 43 (2017). https://doi.org/10.1007/s00348-017-2308-z

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s00348-017-2308-z

Keywords

Search

Navigation