Skip to main content
    • Aa
    • Aa

Global density effects on the self-preservation behaviour of turbulent free jets

  • C. D. Richards (a1) (a2) and W. M. Pitts

An experimental investigation was designed to test the hypothesis that all axisymmetric turbulent free jets become asymptotically independent of the source conditions and may be described by classical similarity analysis. Effects of initial conditions were studied by varying jet exit boundary conditions and the global density ratio. The exit velocity profile and turbulence level was changed by using both pipe and nozzle flow hardware. Initial density differences were imposed by using three gases: helium, methane, and propane. The scalar field (concentration) in the momentum-dominated regime of the far field (10 to 60 jet exit diameters downstream) of turbulent free jets was characterized using Rayleigh light scattering as the diagnostic. The results show that regardless of the initial conditions axisymmetric turbulent free jets decay at the same rate, spread at the same angle, and both the mean and r.m.s. values collapse in a form consistent with full self-preservation. The means and fluctuations follow a law of full self-preservation in which two virtual origins must be specified. The two displacements are required to account for the effects of a finite source of momentum and different development of the velocity and mass distributions in the near fields of the jets. The memory of the jet is embodied in these two virtual origins.

Hide All
Becker, H. A., Hottel, H. C. & Williams, G. C. 1967 The nozzle-fluid concentration field of the round, turbulent, free jet. J. Fluid Mech. 30, 285303.

Birch, A. D., Brown, D. R., Dodson, M. G. & Thomas, J. R. 1978 The turbulent concentration field of a methane jet. J. Fluid Mech. 88, 431449.

Browne, L. W. B., Antonia, R. A. & Chambers, A. J. 1984 The interaction region of a turbulent plane jet. J. Fluid Mech. 149, 355373.

Bryner, N., Richards, C. D. & Pitts, W. M. 1992 A Rayleigh light scattering facility for the investigation of free jets and plumes. Rev. Sci. Instrum. 63, 36293635.

Chambers, F. W. & Goldschmidt, V. W. 1982 Acoustic interaction with a turbulent plane jet: effects on mean flow. AIAA J. 20, 797804.

Dahm, W. A. & Dimotakis, P. E. 1987 Measurements of entrainment and mixing in turbulent jets. AIAA J. 25, 12161223.

Dowling, D. R. & Dimotakis, P. E. 1990 Similarity of the concentration field of gas-phase turbulent jets. J. Fluid Mech. 218, 109141.

Flora, J. J. & Goldschmidt, V. W. 1969 Virtual origins of a free plane turbulent jet. AIAA J. 7, 23442346.

Gouldin, F. C., Schefer, R. W., Johnson, S. C. & Kollmann, W. 1986 Nonreacting turbulent mixing flows. Prog. Energy Combust. Sci. 12, 257303.

Grandmaison, E. W., Rathgeber, D. E. & Becker, H. A. 1982 Some characteristics of concentration fluctuations in free turbulent jets. Can. J. Chem. Engng 60, 212219.

Hussain, A. K. M. F. & Clark, A. R. 1977 Upstream influence on the near field of a plane turbulent jet. Phys. Fluids 20, 14161426.

LaRue, J. C., Libby, P. A. & Seshadri, V. R. 1981 Further results on the thermal mixing layer downstream of a turbulence grid. Phys. Fluids 24, 19271933.

Morton, B. R., Taylor, G. I. & Turner, J. S. 1956 Turbulent gravitational convection from maintained and instantaneous sources. Proc. R. Soc. Lond. 234, 123.

Namazian, M., Schefer, R. W. & Kelly, J. 1988 Scalar dissipation measurements in the developing region of a jet. Combust. Flame 74, 147160.

Papanicolaou, P. N. & List, E. J. 1988 Investigations of round vertical turbulent buoyant jets. J. Fluid Mech. 195, 341391.

Pitts, W. M. & Kashiwagi, T. 1984 The application of laser-induced Rayleigh light scattering to the study of turbulent mixing. J. Fluid Mech. 141, 391429.

Sforza, P. M. & Mons, R. F. 1978 Mass, momentum, and energy transport in turbulent free jets. Intl J. Heat Mass Transfer 21, 371384.

So, R. M. C. & Lui, T. M. 1986 On self-preserving, variable-density, turbulent free jets. Z. Angew. Math. Phys. 37, 538558.

So, R. M. C., Zhu, J. Y. Z., Otugen, M. V. & Huang, B. C. 1990 Some measurements in a binary gas jet. Expts Fluids 9, 273284.

Sunavala, P. D., Hulse, C. & Thring, M. W. 1957 Mixing and combustion in free and enclosed turbulent jet diffusion flames. Combust. Flame 1, 179193.

Wilson, R. A. M. & Danckwerts, P. V. 1964 Studies in turbulent mixing – II a hot jet. Chem. Engng Sci. 19, 885895.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Fluid Mechanics
  • ISSN: 0022-1120
  • EISSN: 1469-7645
  • URL: /core/journals/journal-of-fluid-mechanics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 0
Total number of PDF views: 40 *
Loading metrics...

Abstract views

Total abstract views: 101 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 17th October 2017. This data will be updated every 24 hours.