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Vortical structure in the wake of a transverse jet

  • T. F. Fric (a1) (a2) and A. Roshko (a1)
Abstract

Structural features resulting from the interaction of a turbulent jet issuing transversely into a uniform stream are described with the help of flow visualization and hot-wire anemometry. Jet-to-crossflow velocity ratios from 2 to 10 were investigated at crossflow Reynolds numbers from 3800 to 11400. In particular, the origin and formation of the vortices in the wake are described and shown to be fundamentally different from the well-known phenomenon of vortex shedding from solid bluff bodies. The flow around a transverse jet does not separate from the jet and does not shed vorticity into the wake. Instead, the wake vortices have their origins in the laminar boundary layer of the wall from which the jet issues. It is argued that the closed flow around the jet imposes an adverse pressure gradient on the wall, on the downstream lateral sides of the jet, provoking 'separation events’ in the wall boundary layer on each side. These result in eruptions of boundary-layer fluid and formation of wake vortices that are convected downstream. The measured wake Strouhal frequencies, which depend on the jet-crossflow velocity ratio, match the measured frequencies of the separation events. The wake structure is most orderly and the corresponding wake Strouhal number (0.13) is most sharply defined for velocity ratios near the value 4. Measured wake profiles show deficits of both momentum and total pressure.

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Becker, H. A. & Massaro, T. A. 1968 Vortex evolution in a round jet. J. Fluid Mech. 31, 435448.

Broadwell, J. E. & Breidenthal, R. E. 1984 Structure and mixing of a transverse jet in incompressible flow. J. Fluid Mech. 148, 405412.

Chaissang, P., George, J., Claria, A. & Sananes, F. 1974 Physical characteristics of subsonic jets in a cross stream. J. Fluid Mech. 62, 4164.

Couder, V. & Basdevant, C. 1986 Experimental and numerical study of vortex couples in two-dimensional flows. J. Fluid Mech. 173, 225251.

Fearn, R. & Weston, R. P.1974Vorticity associated with a jet in a cross flow. AIAA J.12, 16661671.

Freymuth, P. 1986 On transition in a separated laminar boundary layer. J. Fluid Mech. 25, 683704.

Fric, T. F. & Roshko, A.1988Views of the transverse jet near field. Phys. Fluids31, 2390.

Gutmark, E. & Ho, C. M.1983Preferred modes and the spreading rates of jets. Phys. Fluids26, 29322938.

Jacobs, J. W. 1992 Shock-induced mixing of a light-gas cylinder. J. Fluid Mech. 234, 629649.

Kamotani, Y. & Greber, I.1972Experiments on a turbulent jet in a crossflow. AIAA J.10, 14251429.

Keffer, J. F. & Baines, W. D. 1963 The round turbulent jet in a cross-wind. J. Fluid Mech. 15, 481496.

Kiya, M., Ohyama, M. & Hunt, J. C. R. 1986 Vortex pairs and rings interacting with shear layer vortices. J. Fluid Mech. 172, 115.

Lozano, A., Smith, S. H., Mungal, M. G. & Hanson, R. K.1994Concentration measurements in a transverse jet by planar laser-induced fluorescence of acetone. AIAA J.32, 218221.

McMahon, H. M., Hester, D. D. & Palfrey, J. G. 1971 Vortex shedding from a turbulent jet in a cross-wind. J. Fluid Mech. 48, 7380.

Morton, B. R.1984The generation and decay of vorticity. Geophys. Astrophys. Fluid Dyn.28, 277308.

Moussa, Z. M., Trischka, J. W. & Eskanazi, S. 1977 The near field in the mixing of a round jet with a cross-stream. J. Fluid Mech. 80, 4980.

Thwaites, B. 1949 Approximate calculation of the laminar boundary layer. Aero. Q. 1. 245280.

Wu, J. M., Vakili, A. D. & Yu, F. M.1988Investigation of the interacting flow of nonsymmetric jets in crossflow. AIAA J.26, 940947.

Wu, J. Z., Gu, J. W. & Wu, J. M.1987Steady three-dimensional fluid particle separation from arbitrary smooth surface and formation of free vortex layers. 5th AIAA Appl. Aerodyn. Conf. Monterey.

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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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