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Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets

  • FABRICE SCHLEGEL (a1), DAEHYUN WEE (a2), YOUSSEF M. MARZOUK (a3) and AHMED F. GHONIEM (a1)
Abstract

Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in terms of vorticity generation along the channel wall, captures unsteady interactions between the wall boundary layer and the jet – in particular, the separation of the wall boundary layer and its transport into the interior. For comparison, we also implement a reduced boundary condition that suppresses the separation of the wall boundary layer away from the jet nozzle. By contrasting results obtained with these two boundary conditions, we characterize near-field vortical structures formed as the wall boundary layer separates on the backside of the jet. Using various Eulerian and Lagrangian diagnostics, it is demonstrated that several near-wall vortical structures are formed as the wall boundary layer separates. The counter-rotating vortex pair, manifested by the presence of vortices aligned with the jet trajectory, is initiated closer to the jet exit. Moreover tornado-like wall-normal vortices originate from the separation of spanwise vorticity in the wall boundary layer at the side of the jet and from the entrainment of streamwise wall vortices in the recirculation zone on the lee side. These tornado-like vortices are absent in the case where separation is suppressed. Tornado-like vortices merge with counter-rotating vorticity originating in the jet shear layer, significantly increasing wall-normal circulation and causing deeper jet penetration into the crossflow stream.

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Corresponding author
Email address for correspondence: schlegel@mit.edu
References
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Broadwell J. E. & Breidenthal R. E. 1984 Structure and mixing of a transverse jet in incompressible-flow. J. Fluid Mech. 148, 405412.
Coelho S. L. V. & Hunt J. C. R. 1989 The dynamics of the near-field of strong jets in crossflows. J. Fluid Mech. 200, 95120.
Cortelezzi L. & Karagozian A. R. 2001 On the formation of the counter-rotating vortex pair in transverse jets. J. Fluid Mech. 446, 347373.
Cottet G.-H. & Koumoutsakos P. D. 2000 Vortex Methods: Theory and Practice. Cambridge University Press.
Fric T. F. & Roshko A. 1994 Vortical structure in the wake of a transverse jet. J. Fluid Mech. 279, 147.
Kamotani Y. & Greber I. 1972 Experiments on a turbulent jet in a cross flow. AIAA J. 10, 14251429.
Keffer J. F. & Baines W. D. 1962 The round turbulent jet in a cross-wind. J. Fluid Mech. 15, 481496.
Kelso R. M., Lim T. T. & Perry A. E. 1996 An experimental study of round jets in cross-flow. J. Fluid Mech. 306, 111144.
Leonard A. 1985 Computing three-dimensional incompressible flows with vortex elements. Annu. Rev. Fluid Mech. 17, 523559.
Lim T. T., New T. H. & Luo S. C. 2001 On the development of large-scale structures of a jet normal to a cross flow. Phys. Fluids 13 (3), 770775.
Lindsay K. & Krasny R. 2001 A particle method and adaptive treecode for vortex sheet motion in three-dimensional flow. J. Comput. Phys. 172 (2), 879907.
Majda A. & Bertozzi A. L. 2002 Vorticity and Incompressible Flow. Cambridge University Press.
Margason R. J. 1968 The path of a jet directed at large angles to a subsonic free stream. NASA Technical Note D-4919.
Marzouk Y. M. & Ghoniem A. F. 2005 k-means clustering for optimal partitioning and dynamic load balancing of parallel hierarchical N-body simulations. J. Comput. Phys. 207, 493528.
Marzouk Y. M. & Ghoniem A. F. 2007 Vorticity structure and evolution in a transverse jet. J. Fluid Mech. 575, 267305.
Moore D. W. 1972 Finite amplitude waves on aircraft trailing vortices. Aeronaut. Q. 23, 307314.
Muppidi S. & Mahesh K. 2005 Study of trajectories of jets in crossflow using direct numerical simulations. J. Fluid Mech. 530, 81100.
Rosenhead L. 1931 The formation of vortices from a surface of discontinuity. Proc. R. Soc. A 134, 170192.
Schlegel F., Wee D. & Ghoniem A. F. 2008 A fast 3d particle method for the simulation of buoyant flow. J. Comput. Phys. 227 (21), 90639090.
Smith S. H. & Mungal M. G. 1998 Mixing, structure, and scaling of the jet in crossflow. J. Fluid Mech. 357, 83122.
Wee D. & Ghoniem A. F. 2006 Modified interpolation kernels for diffusion and remeshing in vortex methods. J. Comput. Phys. 213, 239263.
Wu J. M., Vakili A. D. & Yu F. M. 1988 Investigation of the interacting flow of nonsymmetric jets in crossflow. AIAA J. 26, 940947.
Yuan L. L., Street R. L. & Ferziger J. H. 1999 Large-eddy simulations of a round jet in crossflow. J. Fluid Mech. 379, 71104.
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Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
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