Hostname: page-component-848d4c4894-nr4z6 Total loading time: 0 Render date: 2024-04-30T23:38:14.629Z Has data issue: false hasContentIssue false

Role of coherent structures in multiple self-similar states of turbulent planar wakes

Published online by Cambridge University Press:  22 August 2013

Jean-Pierre Hickey*
Affiliation:
Department of Mechanical and Aerospace Engineering, Royal Military College of Canada, Kingston, Ontario K7K 7B4, Canada
Fazle Hussain
Affiliation:
Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA
Xiaohua Wu
Affiliation:
Department of Mechanical and Aerospace Engineering, Royal Military College of Canada, Kingston, Ontario K7K 7B4, Canada
*
Present address: Center for Turbulence Research, Stanford University, CA 94305, USA. Email address for correspondence: jphickey@stanford.edu

Abstract

We study the nature of archetypal, incompressible, planar splitter-plate wakes, specifically the effects of the exit boundary layer state on multiple approximate self-similarity. Temporally developing direct numerical simulations, at a Reynolds number of 1500 based on the volume-flux defect, are performed to investigate three distinct wake evolution scenarios: Kelvin–Helmholtz transition, bypass transition in an asymmetric wake, and an initially fully turbulent wake. The differences in the evolution and far-wake statistics are analysed in detail. The individual approximately self-similar states exhibit a relative variation of up to 48 % in the spread rate, in second-order statistics, and in peak values of the energy budget terms. The multiplicity of self-similar states is tied to the non-universality of the large-scale coherent structures. These structures maintain the memory of the initial conditions. In the far wake, two distinct spanwise-coherent motions are identified: (i) staggered, segregated spanwise rollers on either side of the centreplane, dominant in wakes transitioning via anti-symmetric instability modes; and, (ii) larger spanwise rollers spanning across the centreplane, emerging in the absence of a near-wake characteristic length scale. The latter structure is characterized by strong spanwise coherence, cross-wake velocity correlations and a larger entrainment rate caused by deep pockets of irrotational fluid within the folds of the turbulent/non-turbulent interface. The mid-sized structures, primarily vortical rods, are generic for all initial conditions and are inclined at ∼$\pm 3{3}^{\circ } $ to the downstream, shallower than the preferential $\pm 4{5}^{\circ } $ inclination of the vorticity vector. The spread rate is driven by the inner-wake dynamics, more specifically the advective flux of spanwise vorticity across the centreplane, which depends on the large-scale coherent structures.

Type
Papers
Copyright
©2013 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

Althaus, W. 1990 Experimental investigation of vortex formation in the wake of a flat plate for subsonic and supersonic free stream Mach numbers. Exp. Fluids 9, 267272.Google Scholar
Antonia, R. A., Browne, L. W. B., Bisset, D. K. & Fulachier, L. 1987 A description of the organized motion in the turbulent far wake of a cylinder at low Reynolds number. J. Fluid Mech. 184, 423444.Google Scholar
Bell, J. H. & Mehta, R. D. 1990 Development of a two-stream mixing layer from tripped and untripped boundary layers. AIAA J. 28 (12), 20342042.CrossRefGoogle Scholar
Bevilaqua, P. M. & Lykoudis, P. S. 1978 Turbulence memory in self-preserving wakes. J. Fluid Mech. 89, 589606.CrossRefGoogle Scholar
Bisset, D. K., Antonia, R. & Browne, L. W. B. 1990a Spatial organization of large structures in the turbulent far wake of a cylinder. J. Fluid Mech. 218, 439461.CrossRefGoogle Scholar
Bisset, D. K., Antonia, R. A. & Britz, D. 1990b Structures of large-scale vorticity in a turbulent far wake. J. Fluid Mech. 218, 463482.Google Scholar
Bisset, D. K., Hunt, J. C. R. & Rogers, M. M. 2002 The turbulent/non-turbulent interface bounding a far wake. J. Fluid Mech. 451, 383410.Google Scholar
Bonnet, J.-P. & Chaput, E. 1986 Large-scale structures visualization in a high-Reynolds number turbulent flat plate wake at supersonic speeds. Exp. Fluids 4, 350356.Google Scholar
Bonnet, J.-P., Delville, J. & Garem, H. 1986 Space and space-time longitudinal velocity correlations in the turbulent far wake of a flat plate in incompressible flow. Exp. Fluids 4, 189196.Google Scholar
Bonnet, J.-P., Jayaraman, V. & Alziary de Roquefort, T. 1984 Structure of a high-Reynolds number turbulent wake in supersonic flow. J. Fluid Mech. 143, 277304.Google Scholar
Breidenthal, R. 1980 Response of plane shear layers and wakes to strong three-dimensional disturbances. Phys. Fluids 23, 19291934.CrossRefGoogle Scholar
Brown, G. L. & Roshko, A. 2012 Turbulent shear layers and wakes. J. Turbul. N51, doi:10.1080/14685248.2012.723805.Google Scholar
Browne, L. W. B., Antonia, R. A. & Bisset, D. K. 1986 Coherent structures in the far field of a turbulent wake. Phys. Fluids 29 (11), 36123618.Google Scholar
Chakraborty, P., Balachandar, S. & Adrian, R. J. 2005 On the relationships between local vortex identification schemes. J. Fluid Mech. 535, 189214.CrossRefGoogle Scholar
Chevray, R. & Kovasznay, L. S. G. 1969 Turbulence measurements in the wake of a thin flat plate. AIAA J. 7, 16411643.Google Scholar
Cimbala, J. M., Nagib, H. & Roshko, A. 1988 Large structure in the far wakes of two-dimensional bluff bodies. J. Fluid Mech. 190, 265298.Google Scholar
Ewing, D., George, W. K., Rogers, M. & Moser, R. 2007 Two-point similarity in temporally evolving plane wakes. J. Fluid Mech. 577, 287307.Google Scholar
Ferré, J. A., Mumford, J. C., Savill, A. M. & Giralt, F. 1990 Three-dimensional large-eddy motions and fine-scale activity in a plane turbulent wake. J. Fluid Mech. 210, 371414.Google Scholar
George, W. K. 1989 The Self-Preservation of Turbulent Flows and its Relation to Initial Conditions and Coherent Structures. Advances in Turbulence. Springer.Google Scholar
Ghosal, S. & Rogers, M. M. 1997 A numerical study of self-similarity in a turbulent plane wake using large-eddy simulation. Phys. Fluids 9, 17291739.CrossRefGoogle Scholar
Giralt, F. & Ferré, J. A. 1993 Structure and flow patterns in turbulent wakes. Phys. Fluids A 5, 17831789.CrossRefGoogle Scholar
Grant, M. L. 1958 The large eddies of turbulent motion. J. Fluid Mech. 4, 149190.Google Scholar
Hayakawa, M. & Hussain, F. 1989 Three-dimensionality of organized structures in a plane turbulent wake. J. Fluid Mech. 206, 375404.CrossRefGoogle Scholar
Head, M. R. & Bandyopadhyay, P. 1981 New aspects of turbulent boundary-layer structure. J. Fluid Mech. 107, 297338.Google Scholar
Ho, C. M. & Huerre, P. 1984 Perturbed free shear layers. Annu. Rev. Fluid Mech. 16, 365422.CrossRefGoogle Scholar
Hussain, A. K. M. F. & Clark, A. R. 1977 Upstream influence on the near field of a plane turbulent jet. Phys. Fluids 20, 14611472.Google Scholar
Hussain, A. K. M. F. & Hayakawa, M. 1987 Eduction of large-scale organized structures in a turbulent plane wake. J. Fluid Mech. 180, 193229.Google Scholar
Hussain, A. K. M. F. & Zedan, M. F. 1978a Effects of the initial condition on the axisymmetric free shear layer: effects of the initial momentum thickness. Phys. Fluids 21, 11001112.Google Scholar
Hussain, A. K. M. F. & Zedan, M. F. 1978b Effects of the initial condition on the axisymmetric free shear layer: effect of the initial fluctuation level. Phys. Fluids 21, 14751481.Google Scholar
Jeong, J. & Hussain, F. 1995 On the identification of a vortex. J. Fluid Mech. 285, 6994.Google Scholar
Jeong, J., Hussain, F., Schoppa, W. & Kim, J. 1997 Coherent structures near the wall in a turbulent channel flow. J. Fluid Mech. 332, 185214.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 (3), 603617.CrossRefGoogle Scholar
Julien, S., Lasheras, J. & Chomaz, J.-M. 2003 Three-dimensional instability and vorticity patterns in the wake of a flat plate. J. Fluid Mech. 479, 155189.CrossRefGoogle Scholar
Kopp, G. A., Giralt, F. & Keffer, J. A. 2002 Entrainment vortices and interfacial intermittent turbulent bulges in a plane turbulent wake. J. Fluid Mech. 469, 4970.CrossRefGoogle Scholar
LaRue, J. C. & Libby, P. A. 1974a Temperature and intermittency in the turbulent wake of a heated cylinder. Phys. Fluids 17, 873890.CrossRefGoogle Scholar
LaRue, J. C. & Libby, P. A. 1974b Temperature fluctuations in the plane turbulent wake. Phys. Fluids 17, 19561967.CrossRefGoogle Scholar
LaRue, J. C. & Libby, P. A. 1976 Statistical properties of the interface in the turbulent wake of a heated cylinder. Phys. Fluids 19, 18641875.CrossRefGoogle Scholar
Lasheras, J. C. & Meiburg, E. 1990 Three-dimensional vorticity modes in the wake of a flat plate. Phys. Fluids A 2, 371381.CrossRefGoogle Scholar
Lepore, J. & Mydlarski, L. 2009 Effect of the scalar injection mechanism on passive scalar structure functions in a turbulent. Phys. Rev. Lett. 103, 034501.Google Scholar
Lesieur, M. 1997 Turbulence in Fluids (3rd rev.). Kluwer.Google Scholar
Maekawa, H., Mansour, N. N. & Buell, J. C. 1992 Instability mode interactions in a spatially developing plane wake. J. Fluid Mech. 235, 223254.CrossRefGoogle Scholar
Marasli, B., Champagne, F. & Wygnanski, I. 1992 Effect of travelling waves on the growth of a plane turbulent wake. J. Fluid Mech. 235, 511528.Google Scholar
Moser, R. D., Rogers, M. M. & Ewing, D. W. 1998 Self-similarity of time-evolving plane wakes. J. Fluid Mech. 367, 255289.Google Scholar
Mumford, J. C. 1983 The structure of the large eddies in fully developed turbulent shear flows. Part 2. The plane wake. J. Fluid Mech. 137, 447456.Google Scholar
Narasimha, R. & Prabhu, A. 1972 Equilibrium and relaxation in turbulent wakes. J. Fluid Mech. 54, 117.Google Scholar
Papageorgiou, D. T. 1990 Linear instability of the supersonic wake behind a flat plate aligned with a uniform stream. Theor. Comput. Fluid Dyn. 1 (6), 327348.Google Scholar
Papageorgiou, D. T. & Smith, F. T. 1989 Linear instability of the wake behind a flat plate placed parallel to a uniform stream. J. Fluid Mech. 208, 6789.Google Scholar
Papailiou, D. D. & Lykoudis, P. S. 1974 Turbulent vortex streets and the entrainment mechanism of the turbulent wake. J. Fluid Mech. 62, 1131.Google Scholar
Payne, F. & Lumley, J. 1967 Large eddy structure of the turbulent wake behind a circular cylinder. Phys. Fluids 9, S194S196.Google Scholar
Philip, J. & Marusic, I. 2012 Large-scale eddies and their role in entrainment in turbulent jets and wakes. Phys. Fluids 24, 055108.CrossRefGoogle Scholar
Rai, M. M. 2010 A computational investigation of symmetric and asymmetric turbulent wakes. AIAA Paper 2010-4602.CrossRefGoogle Scholar
Redford, J. A., Castro, I. & Coleman, G. 2012 On the universality of turbulent axisymmetric wakes. J. Fluid Mech. 710, 419452.CrossRefGoogle Scholar
Robinson, S. K. 1991 Coherent motions in the turbulent boundary layer. Annu. Rev. Fluid Mech. 23, 601639.Google Scholar
Robinson, A. C. & Saffman, P. G. 1982 Three-dimensional stability of vortex arrays. J. Fluid Mech. 125, 411427.Google Scholar
Sato, H. & Kuriki, K. 1961 The mechanism of transition in the wake of a thin flat plate placed parallel to a uniform flow. J. Fluid Mech. 11, 321352.Google Scholar
Schoppa, W., Hussain, F. & Metcalfe, R. W. 1995 A new mechanism of small-scale transition in a plane mixing layer: core dynamics of spanwise vortices. J. Fluid Mech. 298, 2380.Google Scholar
da Silva, C. B. & Pereira, J. C. 2008 Invariants of the velocity-gradient, rate-of-strain, and rate-of-rotation tensors across the turbulent/non-turbulent interface in jets. Phys. Fluids 20, 055101.Google Scholar
da Silva, C. B. & dos Reis, R. J. 2011 The role of coherent vortices near the turbulent/non-turbulent interface in a planar jet. Phil. Trans. R. Soc. Lond. A 369, 738753.Google Scholar
da Silva, C. B., dos Reis, R. & Pereira, J. C. 2011 The intense vorticity structures near the turbulent/non-turbulent interface in a jets. J. Fluid Mech. 685, 165190.CrossRefGoogle Scholar
Taneda, S. 1959 Downstream development of the wakes behind cylinders. J. Phys. Soc. Japan 14, 843848.Google Scholar
Thomas, F. O. & Liu, X. 2004 An experimental investigation of symmetric and asymmetric turbulent wake development in pressure gradient. Phys. Fluids 16, 17251745.CrossRefGoogle Scholar
Thompson, K. W. 1987 Time dependent boundary conditions for hyperbolic systems. J. Comput. Phys. 68, 124.CrossRefGoogle Scholar
Thompson, K. W. 1990 Time-dependent boundary conditions for hyperbolic systems, ii. J. Comput. Phys. 89, 439461.CrossRefGoogle Scholar
Townsend, A. A. 1949 The fully developed turbulent wake of a circular cylinder. Austral. J. Sci. Res. 2 (4), 451468.Google Scholar
Townsend, A. A. 1976 The Structure of Turbulent Shear Flow. Cambridge University Press.Google Scholar
Vanderwel, C. & Tavoularis, S. 2011 Coherent structures in uniformly sheared turbulent flow. J. Fluid Mech. 689, 434464.Google Scholar
Vernet, A., Kopp, G. A., Ferré, J. A. & Giralt, F. 1999 Three-dimensional structure and momentum transfer in a turbulent cylinder wake. J. Fluid Mech. 394, 303337.CrossRefGoogle Scholar
Voke, P. R. & Potamitis, S. G. 1994 Numerical simulation of a low-Reynolds number turbulent wake behind a flat-plate. Intl J. Numer. Meth. Fluids 19, 377393.Google Scholar
Weygandt, J. H. & Mehta, R. D. 1989 Asymptotic behavivor of a flat plate wake. Tech. Rep. JIAA Tr-95. Stanford University.Google Scholar
Williamson, C. H. K. & Prasad, A. 1993 A new mechanism for oblique wave resonance in the ‘natural’ far wake. J. Fluid Mech. 256, 269313.Google Scholar
Winant, C. D. & Browand, F. K. 1974 Vortex pairing: the mechanism of turbulent mixing-layer growth at moderate Reynolds number. J. Fluid Mech. 63, 237255.Google Scholar
Wu, X. & Hickey, J. P. 2012 Visualization of continuous stream of grid turbulence past the Langston turbine cascade. AIAA J. 50 (1), 215224.CrossRefGoogle Scholar
Wu, X. & Moin, P. 2009 Direct numerical simulation of turbulence in a nominally zero-pressure-gradient flat-plate boundary layer. J. Fluid Mech. 630, 541.CrossRefGoogle Scholar
Wu, X. & Moin, P. 2010 Transitional and turbulent boundary layer with heat transfer. Phys. Fluids 22, 085105.Google Scholar
Wygnanski, I., Champagne, F. & Marasli, B. 1986 On the large-scale structures in two-dimensional, small-deficit, turbulent wakes. J. Fluid Mech. 168, 3171.Google Scholar
Zaman, K. B. M. Q. & Hussain, A. K. M. F. 1980 Vortex pariring in a circular jet under controlled excitation: part 1. General jet response. J. Fluid Mech. 101, 449491.Google Scholar
Zhou, J., Adrian, R., Balachandar, S. & Kendall, J. 1999 Mechanisms for generating coherent packets of hairpin vortices in channel flow. J. Fluid Mech. 387, 353396.Google Scholar
Zhou, Y. & Antonia, R. A. 1995 Memory effects in a turbulent plane wake. Exp. Fluids 19, 112120.CrossRefGoogle Scholar