Hostname: page-component-6bf8c574d5-b4m5d Total loading time: 0 Render date: 2025-02-15T18:38:20.594Z Has data issue: false hasContentIssue false
  • English
  • Français

Conditionally sampled measurements in a heated turbulent jet

Published online by Cambridge University Press:  29 March 2006

R. A. Antonia ,
A. Prabhu  and
S. E. Stephenson
R. A. Antonia
Affiliation:
Department of Mechanical Engineering, University of Sydney, New South Wales 2006, Australia
A. Prabhu
Affiliation:
Department of Mechanical Engineering, University of Sydney, New South Wales 2006, Australia
S. E. Stephenson
Affiliation:
Department of Mechanical Engineering, University of Sydney, New South Wales 2006, Australia
Get access Rights & Permissions [Opens in a new window]

Abstract

Measurements of velocity fluctuations u (axial) and v (radial) and temperature fluctuations θ averaged over the turbulent zone have been made in a turbulent heated jet with a co-flowing stream and compared with the conventionally averaged results. The zone-averaged mean temperature and temperature fluctuation intensity appear to be nearly homogeneously distributed in the outer, intermittent region of the jet. This homogeneity does not apply to the u and v fluctuations. The flatness factor of the temperature within the turbulent part of the flow is remarkably constant throughout the intermittent region. Although the skewness of the turbulent θ fluctuations is non-zero, it is smaller than the skewness of the turbulent u and v fluctuations. The average $\overline{\theta v}$ of the heat flux over the turbulent zone increases in the intermittent region whereas the zone-averaged momentum flux $\overline{uv}$ and zone-averaged heat flux $\overline{\theta u}$ continuously decrease. This leads to the Prandtl number of the turbulent fluid being smaller than the conventional Prandtl number in the outer part of the flow. A budget for the square of the temperature fluctuations within the turbulent part of the flow indicates a constant distribution of temperature dissipation. The transport of heat by the large-scale structure of the flow is briefly discussed in the light of available experimental information on other turbulent shear flows.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 72 , Issue 3 , 9 December 1975 , pp. 455 - 480
Copyright
© 1975 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

Antonia, R. A. 1972 Conditionally sampled measurements near the outer edge of a turbulent boundary layer. J. Fluid Mech. 56, 1.Google Scholar
Antonia, R. A. 1974 The distribution of temperature in the intermittent region of a turbulent shear flow. In Proc. 5th Int. Heat Transfer Conf., Tokyo, vol. 2, p. 95.
Antonia, R. A. & Atkinson, J. D. 1974 Use of a pseudo-turbulent signal to calibrate an intermittency measuring circuit. J. Fluid Mech. 64, 679.Google Scholar
Antonia, R. A. & Bilger, R. W. 1973 An experimental investigation of an axisymmetric jet in a co-flowing air stream. J. Fluid Mech. 61, 805.Google Scholar
Antonia, R. A. & Bilger, R. W. 1974 The heated round turbulent jet in a co-flowing stream. Charles Kolling Res. Lab., Dept. Mech. Engng, University of Sydney, Tech. Note, F-66.
Antonia, R. A. & Van atta, C. W. 1975 On the correlation between temperature and velocity dissipation fields in a heated turbulent jet. J. Fluid Mech. 67, 273.Google Scholar
Bradshaw, P. 1966 The turbulence structure of equilibrium boundary layers. Nat. Phys. Lab. Aero. Rep. no. 1184.Google Scholar
Bradshaw, P. & Murlis, J. 1973 On the measurement of intermittency in turbulent flow. Imp. Coll. Aero. Tech. Note, no. 73–108.
Brown, G. L. & Roshko, A. 1974 On the density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64, 775.Google Scholar
Fiedler, H. 1974 Transport of heat across a plane turbulent mixing layer. Adv. in Geophys. 18, 93.Google Scholar
Freymuth, P. & Uberoi, M. S. 1971 Structure of temperature fluctuations in the turbulent wake behind a heated cylinder. Phys. Fluids, 14, 2574.Google Scholar
Freymuth, P. & Uberoi, M. S. 1973 Temperature fluctuations in a turbulent wake behind an optically heated sphere. Phys. Fluids, 16, 161.Google Scholar
Fulachier, L. 1972 Contribution à l’étude des analogies des champs dynamique et thermique dans une couche limite turbulente. Effet de l'aspiration. D.Sc. thesis, Institut de Mécanique Statistique de la Turbulence, Université de Provence, Marseille.
Hedley, T. B. & Keffer, J. F. 1974 Some turbulent/non-turbulent properties of the outer intermittent region of a boundary layer. J. Fluid Mech. 64, 645.Google Scholar
Kovasznay, L. S. G. & Ali, S. F. 1974 Structure of the turbulence in the wake of a heated flat plate. In Proc. 5th Int. Heat Transfer Conf. Tokyo, vol. 2, p. 99.
Kovasznay, L. S. G., Kibens, V. & Blackwelder, R. F. 1970 Large scale motion in the intermittent region of a turbulent boundary layer. J. Fluid Mech. 41, 283.Google Scholar
Larue, J. C. & Libby, P. A. 1974a Temperature and intermittency in the turbulent wake of a heated cylinder. Phys. Fluids, 17, 873.Google Scholar
Larue, J. C. & Libby, P. A. 1974b Temperature fluctuations in the plane turbulent wake. Phys. Fluids, 17, 1956.Google Scholar
Stellema, L., Antonia, R. A. & Prabhu, A. 1975 A constant-current resistance thermometer for the measurement of mean and fluctuating temperatures in turbulent flows. Charles Kolling Res. Lab., Dept. Mech. Engng, University of Sydney, Tech. Note, D-12.
Sunyach, M. 1971 Contribution à l’étude des frontières d’écoulements turbulents libres. D.Sc. thesis, Université Claude Bernard de Lyon.
Sunyach, M. & Mathieu, J. 1969 Zone de mélange d'un jet plan. Int. J. Heat Mass Transfer, 12, 1679.Google Scholar
Thomas, R. M. 1973 Conditional sampling and other measurements in a plane turbulent wake. J. Fluid Mech. 57, 549.Google Scholar
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow. Cambridge University Press.
Wilson, R. A. M. & Danckwerts, P. V. 1964 Studies in turbulent mixing. II. A hot-air jet. Chem. Engng Sci. 19, 885.Google Scholar
Wygnanski, I. & Fiedler, H. E. 1969 Some measurements in the self-preserving jet. J. Fluid Mech. 38, 577.Google Scholar
Wygnanski, I. & Fiedler, H. E. 1970 The two-dimensional mixing region. J. Fluid Mech. 41, 327.Google Scholar
Wyngaard, J. C. 1971 The effect of velocity sensitivity on temperature derivative statistics in isotropic turbulence. J. Fluid Mech. 48, 763.Google Scholar