Abstract
The generation of a hairpin vortex from near-wall streamwise vortices is studied via the direct numerical simulation (DNS) of the streak transient growth in the minimal channel flow at \(Re_\tau =400\). The streak profile is obtained by conditionally averaging the DNS data of the fully developed turbulent channel flow at the same Reynolds number. The near-wall streamwise vortices are produced by the transient growth of the streak which is initially subjected to the sinuous perturbation of the spanwise velocity. It is shown that the arch head of the hairpin vortex first grows from the downstream end of the stronger streamwise vortex and then connects with the weaker, opposite-signed streamwise vortex in their overlap region, forming a complete individual hairpin structure. The vorticity transport along the vortex lines indicates that the strength increase and the spatial expansion of the arch head are due to the stretching and the turning of the vorticity vector, respectively. The hairpin packets could be further produced from the generated individual hairpin vortex following the parent-offspring process.
Graphical Abstract
Generation of hairpin vortex from a pair of counter-rotating streamwise vortices due to stretching and turning effects. (a1)(b1)(c1) perspective view of vortex and strain vectors; (a2)(b2)(c2) distribution of stretching and turning terms along the vortex line projected to y - z plane. Meshed surface: \(\lambda _{ci} = 10\); black vector: strain vector; red solid line: vortex line; dashed line: turning; dash-dotted line: stretching.
Similar content being viewed by others
References
Theodorsen, T.: Mechanism of turbulence. In: Proceedings of the Second Midwestern Conference on Fluid Mechanics, Ohio State University, pp. 1–18 (1952)
Robinson S.K.: The kinematics of turbulent boundary layer structure. Ph.D Thesis, Department of Mechanical Engineering, Stanford University (1991)
Head, M.R., Bandyopadhyay, P.: New aspects of turbulent boundary-layer structure. J. Fluid Mech. 107, 297–338 (1981)
Meinhart, C.D., Adrian, R.J.: On the existence of uniform momentum zones in a turbulent boundary layer. Phys. Fluid 7, 694–696 (1995)
Adrian, R.J., Meinhart, C.D., Tomkins, C.D.: Vortex organization in the outer region of the turbulent boundary layer. J. Fluid Mech. 422, 1–54 (2000)
Christensen, K.T., Adrian, R.J.: Statistical evidence of hairpin vortex packets in wall turbulence. J. Fluid Mech. 431, 433–443 (2001)
Gao, Q., Ortiz-Duenas, C., Longmire, E.K.: Analysis of vortex populations in turbulent wall-bounded flows. J. Fluid Mech. 678, 87–123 (2011)
Kim, J., Moin, P., Moser, R.: Turbulence statistics in fully developed channel flow at low Reynolds number. J. Fluid Mech. 177, 133–166 (1987)
Chacin, J.M., Cantwell, B.J., Kline, S.J.: Study of turbulent boundary layer structure using the invariants of the velocity gradient tensor. Exp. Therm. Fluid Sci. 13, 308–317 (1996)
Adrian, R.J., Liu, Z.C.: Observation of vortex packets in direct numerical simulation of fully turbulent channel flow. J. Vis. 5, 9–19 (2002)
Berlin, S., Wiegel, M., Henningson, D.S.: Numerical and experimental investigations of oblique boundary layer transition. J. Fluid Mech. 393, 23–57 (1999)
Borodulin, V.I., Kachanov, Y.S., Roschektayev, A.P.: Experimental detection of deterministic turbulence. J. Turbul. 12, N23 (2011)
Wu, X.H., Moin, P.: Forest of hairpins in a low-Reynolds-number zero-pressure-gradient flat-plate boundary layer. Phys. Fluid 21, 091106 (2009)
Wu, X.H., Moin, P.: Transitional and turbulent boundary layer with heat transfer. Phys. Fluid 22, 085105 (2010)
Schlatter P., Orlu R., Li Q., et al.: Progress in simulations of turbulent boundary layers. In: 7th International Symposium on Turbulence and Shear Flow Phenomena, Ottawa, Canada (2011)
Adrian, R.J.: Hairpin vortex organization in wall turbulence. Phys. Fluid 19, 041301 (2007)
Lee, J.H., Sung, H.J.: Very-large-scale motions in a turbulent boundary layer. J. Fluid Mech. 673, 80–120 (2011)
Balakumar, B.J., Adrian, R.J.: Large- and very-large-scale motions in channel and boundary-layer flows. Philos. Trans. R. Soc. A 265, 665–681 (2007)
Hutchins, N., Marusic, I.: Evidence of very long meandering features in the logarithmic region of turbulent boundary layers. J. Fluid Mech. 579, 1–28 (2007)
Smith, C.R., Walker, J.D.A.: Turbulent wall-layer vortices. Fluid Vortices 30, 235–289 (1995)
Zhou, J., Adrian, R.J., Balachandar, S., et al.: Mechanisms for generating coherent packets of hairpin vortices in channel flow. J. Fluid Mech. 387, 353–396 (1999)
Goudar M.V., Breugem W.P., Elsinga G.E.: Merging and auto-generation of vortices in wall bounded flows. In: 8th International Symposium on Turbulence and Shear Flow Phenomena, Poitiers, France (2013)
Guo, H., Borodulin, V.I., Kachanov, Y.S., et al.: Nature of sweep and ejection events in transitional and turbulent boundary layers. J. Turbul. 11, N34 (2010)
Skote, M., Haritonidis, J.H., Henningson, D.S.: Varicose instabilities in turbulent boundary layers. Phys. Fluid 14, 7 (2002)
Asai, M., Minagawa, M., Nishioka, M.: The instability and breakdown of a near-wall low-speed streak. J. Fluid Mech. 455, 289–314 (2002)
Chernoray, V.G., Kozlov, V.V., Lofdahl, L., et al.: Visualization of sinusoidal and varicose instabilities of streaks in a boundary layer. J. Vis. 9(4), 437–444 (2006)
Hamilton, J.M., Kim, J., Waleffe, F.: Regeneration mechanism of near-wall turbulence structures. J. Fluid Mech. 287, 317–348 (1995)
Schoppa, W., Hussain, F.: Coherent structure generation in near-wall turbulence. J. Fluid Mech. 453, 57–108 (2002)
Deng, B.Q., Xu, C.X.: Influence of active control on STG-based generation of streamwise vortices in near-wall turbulence. J. Fluid Mech. 710, 234–259 (2012)
Jiménez, J., Pinelli, A.: The autonomous cycle of near-wall turbulence. J. Fluid Mech. 389, 335–359 (1999)
Brandt, L., de Lange, H.C.: Streak interactions and breakdown in boundary layer flows. Phys. Fluids 20, 024107 (2008)
Andersson, P., Brandt, L., Bottaro, A., et al.: On the breakdown of boundary layer streaks. J. Fluid Mech. 428, 29–60 (2001)
Haepffner, J., Brandt, L., Henningson, D.S.: Transient growth on boundary layer streaks. J. Fluid Mech. 537, 91–100 (2005)
Cossu, C., Chevalier, M., Henningson, D.S.: Optimal secondary energy growth in a plane channel flow. Phys. Fluid 19, 058107 (2007)
Cossu, C., Brandt, L., Bagheri, S., et al.: Secondary threshold amplitudes for sinuous streak breakdown. Phys. Fluids 23, 074103 (2011)
Acarlar, M.S., Smith, C.R.: A study of hairpin vortices in a laminar boundary layer. Part 2. Hairpin vortices generated by fluid injection. J. Fluid Mech. 175, 43 (1987)
Jiménez, J., Moin, P.: The minimal flow unit in near-wall turbulence. J. Fluid Mech. 225, 213 (1991)
Chakraborty, P., Balachandar, S., Adrian, R.J.: On the relationships between local vortex identification schemes. J. Fluid Mech. 535, 189–214 (2005)
Panton, R.L.: Overview of the self-sustaining mechanisms of wall turbulence. Prog. Aerosp. Sci. 37, 341–383 (2001)
Kim, H., Sung, H.J., Adrian, R.J.: Effects of background noise on generating coherent packets of hairpin vortices. Phys. Fluids 20, 105107 (2008)
Acknowledgments
This project was supported by the National Natural Science Foundation of China (Grants 11490551, 11472154, 11132005, and 11322221).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Wang, Y., Huang, W. & Xu, C. On hairpin vortex generation from near-wall streamwise vortices. Acta Mech Sin 31, 139–152 (2015). https://doi.org/10.1007/s10409-015-0415-8
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10409-015-0415-8