Hostname: page-component-76fb5796d-9pm4c Total loading time: 0 Render date: 2024-04-26T12:35:08.224Z Has data issue: false hasContentIssue false
  • English
  • Français

On the peculiar structure of a helical wake vortex behind an inclined prolate spheroid

Published online by Cambridge University Press:  19 July 2016

Fengjian Jiang Open the ORCID record for Fengjian Jiang [Opens in a new window] ,
Helge I. Andersson ,
José P. Gallardo  and
Valery L. Okulov
Fengjian Jiang*
Affiliation:
Department of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway Huazhong University of Science and Technology, 430074 Wuhan, PR China
Helge I. Andersson
Affiliation:
Department of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
José P. Gallardo
Affiliation:
Department of Marine Technology, NTNU, 7491 Trondheim, Norway
Valery L. Okulov
Affiliation:
Department of Wind Energy, Technical University of Denmark, 2800 Lyngby, Denmark Institute of Thermophysics, SB of RAS, 630090 Novosibirsk, Russia
*
†Email address for correspondence: fengjian.jiang@ntnu.no
Get access Rights & Permissions [Opens in a new window]

Abstract

The self-similarity law for axisymmetric wakes has for the first time been examined and verified in a complex helical vortex in the far part of an asymmetric wake by means of direct numerical simulation (DNS). The helical vortex is the main coherent flow structure in the transitional non-axisymmetric wake behind an inclined 6:1 prolate spheroid at Reynolds number 3000 based on the minor axis. The gradual development of the complex helical vortex structure has been described in detail all the way from its inception at the spheroid and into the far wake. We observed a complex vortex composition in the generation stage, a rare jet-like wake pattern in the near wake and an abrupt change of helical symmetry in the vortex core without an accompanying change in flow topology, i.e. with no recirculation bubble.

JFM classification

Wakes/Jets: Separated flows Vortex Flows: Vortex Flows Wakes/Jets: Wakes
Type
Papers
Information
Journal of Fluid Mechanics , Volume 801 , 25 August 2016 , pp. 1 - 12
Check for updates
Copyright
© 2016 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alekseenko, S. V., Kuibin, P. A. & Okulov, V. L. 2007 Theory of Concentrated Vortices – an Introduction. Springer.Google Scholar
Alekseenko, S. V., Kuibin, P. A., Okulov, V. L. & Shtork, S. I. 1999 Helical vortices in swirl flow. J. Fluid Mech. 382, 195–243.Google Scholar
El Khoury, G. K., Andersson, H. I. & Pettersen, B. 2010 Crossflow past a prolate spheroid at Reynolds number of 10 000. J. Fluid Mech. 659, 365–374.Google Scholar
Faler, J. H. & Leibovich, S. 1977 Disrupted states of vortex flow and vortex breakdown. Phys. Fluids 20, 1385–1400.Google Scholar
Gallardo, J. P., Andersson, H. I. & Pettersen, B. 2014 Turbulent wake behind a curved circular cylinder. J. Fluid Mech. 742, 192–229.CrossRefGoogle Scholar
George, W. K. 1989 The self-preservation of turbulent flows and its relation to initial conditions and coherent structures. In Advances in Turbulence (ed. George, W. K. & Arndt, R. E. A.), pp. 39–73. Hemisphere Publishing Corporation.Google Scholar
Jiang, F., Gallardo, J. P. & Andersson, H. I. 2014 The laminar wake behind a 6:1 prolate spheroid at 45° incidence angle. Phys. Fluids 26, 113602.CrossRefGoogle Scholar
Jiang, F., Gallardo, J. P., Andersson, H. I. & Zhang, Z. 2015 The transitional wake behind an inclined prolate spheroid. Phys. Fluids 27, 093602.Google Scholar
Johansson, P. B. V. & George, W. K. 2006 The far downstream evolution of the high-reynolds-number axisymmetric wake behind a disk. Part 1. Single-point statistics. J. Fluid Mech. 555, 363–386.Google Scholar
Johansson, P. B. V., George, W. K. & Gourlay, M. J. 2003 Equilibrium similarity, effects of initial conditions and local Reynolds number on the axisymmetric wake. Phys. Fluids 15, 603–617.CrossRefGoogle Scholar
Leibovich, S. 1978 The structure of vortex breakdown. Annu. Rev. Fluid Mech. 10, 221–246.CrossRefGoogle Scholar
Leibovich, S. 1984 Vortex stability and breakdown: survey and extension. AIAA J. 22, 1192–1206.Google Scholar
Manhart, M. 2004 A zonal grid algorithm for DNS of turbulent boundary layers. Comput. Fluids 33, 435–461.Google Scholar
Martemianov, S. & Okulov, V. L. 2004 On heat transfer enhancement in swirl pipe flows. Intl J. Heat Mass Transfer 47, 2379–2393.CrossRefGoogle Scholar
Okulov, V. L. 1996 The transition from the right helical symmetry to the left symmetry during vortex breakdown. Tech. Phys. Lett. 22, 798–800.Google Scholar
Okulov, V. L., Naumov, I. V., Mikkelsen, R. F. & Sørensen, J. N. 2015 Wake effect on a uniform flow behind wind-turbine model. J. Phys.: Conf. Ser. 625, 012011.Google Scholar
Okulov, V. L. & Sørensen, J. N. 2010 Applications of 2D helical vortex dynamics. Theor. Comput. Fluid Dyn. 24, 395–401.CrossRefGoogle Scholar
Okulov, V. L., Sørensen, J. N. & Voigt, L. K. 2005 Vortex scenario and bubble generation in a cylindrical cavity with rotating top and bottom. Eur. J. Mech. (B/Fluids) 24, 137–148.Google Scholar
Peller, N., Le Duc, A., Tremblay, F. & Manhart, M. 2006 High-order stable interpolations for immersed boundary methods. Intl J. Numer. Meth. Fluids 52, 1175–1193.Google Scholar
Sarpkaya, T. 1971 On stationary and travelling vortex breakdowns. J. Fluid Mech. 45, 545–559.Google Scholar
Taylor, Z. J., Liberzon, A., Gurka, R., Holzman, R., Reesbeck, T. & Diez, F. J. 2013 Experiments on the vortex wake of a swimming knifefish. Exp. Fluids 54, 1–4.Google Scholar
Velte, C. M., Hansen, M. O. L. & Okulov, V. L. 2009 Helical structure of longitudinal vortices embedded in turbulent wall-bounded flow. J. Fluid Mech. 619, 167–177.Google Scholar
Velte, C. M., Okulov, V. L. & Hansen, M. O. L. 2011 Alteration of helical vortex core without change in flow topology. Phys. Fluids 23, 051707.CrossRefGoogle Scholar