Hostname: page-component-848d4c4894-pjpqr Total loading time: 0 Render date: 2024-06-22T07:11:53.439Z Has data issue: false hasContentIssue false
  • English
  • Français

Simultaneous temperature and velocity measurements in the plane of symmetry of a transitional turbulent spot

Published online by Cambridge University Press:  20 April 2006

R. A. Antonia ,
A. J. Chambers ,
M. Sokolov  and
C. W. Van Atta
R. A. Antonia
Affiliation:
Department of Mechanical Engineering, University of Newcastle, N.S.W., 2308, Australia
A. J. Chambers
Affiliation:
Department of Mechanical Engineering, University of Newcastle, N.S.W., 2308, Australia
M. Sokolov
Affiliation:
School of Engineering, Tel Aviv University, Tel Aviv, 69978, Israel
C. W. Van Atta
Affiliation:
Department of Applied Mechanics and Engineering Sciences, University of California at San Diego, La Jolla, 92093, U.S.A.
Get access Rights & Permissions [Opens in a new window]

Abstract

Simultaneous measurements of the longitudinal velocity U, normal velocity V, and temperature T have been made in turbulent spots generated in a slightly heated laminar boundary layer. The measurements were made in the plane of symmetry of the spot at several streamwise stations downstream of the spot-producing spark. Ensemble averages of U, V and T, obtained relative to the leading edge of the spot, are presented in terms of disturbances relative to the unperturbed values in the laminar flow. Ensemble-averaged disturbances of U, V and T in the outer part of the spot are consistent with a picture of a relatively large vortical structure with a spanwise vorticity in the same sense as that of the laminar flow. A rather dominant feature of these distributions is the large negative disturbance in V and U near the leading edge in the outer part of the spot; associated with this disturbance is a positive perturbation in T. The terms contributing to the ensemble-averaged values of UV, UT and VT are obtained and discussed. In the case of UV, contributions by the disturbance are found to be of the same order as those by the random turbulence superposed on the disturbance. For VT, the disturbance appears to play a more dominant role in the transfer of heat. The conical property of the spot is tested for disturbance temperature and velocity fields by comparing contours, at three streamwise stations, of the velocity and temperature disturbances using the co-ordinates introduced by Cantwell, Coles & Dimotakis (1978). The results show that the conical transformation, which was found to be a good approximation for the full velocity field, is not an accurate representation for the disturbance fields of velocity and temperature measured relative to laminar values. An alternative viscous transformation represents more accurately the disturbance fields. Features of the turbulence within the spot are compared with those obtained in a fully turbulent boundary layer.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 108 , July 1981 , pp. 317 - 343
Copyright
© 1981 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

Amini, J. 1978 Transition contrôlée en couche limite: étude expérimental du développement d'une perturbation tridimensionelle instantanée. Ph.D. thesis, Université Scientifique et Médicale et l'Institut National Polytechnique de Grenoble.
Amini, J. 1979 Development of a laminar spot in a transitional boundary layer. Proc. 7th Canadian Congress Applied Mechanics, Sherbrooke, p. 653.Google Scholar
Bradshaw, P. 1971 An Introduction to Turbulence and its Measurement. Pergamon.
Cantwell, B., Coles, D. & Dimotakis, P. 1978 Structure and entrainment in the plane of symmetry of a turbulent spot. J. Fluid Mech. 87, 641.Google Scholar
Champagne, F. H. 1979 The temperature sensitivity of hot wires. In Proc. Dynamic Flow Conf. 1978, p. 101.
Chen, C. P. & Blackwelder, R. F. 1978 Large scale motion in a turbulent boundary layer: a study using temperature contamination. J. Fluid Mech. 89, 1.Google Scholar
Coles, D. & Barker, S. J. 1975 Some remarks on a synthetic turbulent boundary layer. In Turbulent Mixing in Nonreactive and Reactive Flows (ed. S. N. B. Murthy), p. 285. Plenum.
Emmons, H. W. 1951 The laminar-turbulent transition in a boundary layer. Part I. J. Aero. Sci. 18, 490.Google Scholar
Fiedler, H. 1979 On data acquisition in heated turbulent flows. Proc. Dynamic Flow Conf. 1978, Skovlunde, p. 81.
Fulachier, L. 1972 Contribution à l’étude des analogies des champs dynamique et thermique dans une couche limite turbulente. Effet de l'aspiration. Thèse Docteur ès Sciences, Université de Provence.
Haritonidis, J., Kaplan, R. E. & Wygnanski, I. 1978 Interaction of a turbulent spot with a turbulent boundary layer. In Structure and Mechanisms of Turbulence II (ed. H. Fiedler), Lecture Notes in Physics, vol. 76. Springer.
Head, M. R. & Bandyopadhyay, P. 1978 Combined flow visualization and hot-wire measurements in turbulent boundary layers. In Coherent Structure of Turbulent Boundary Layers (ed. C. R. Smith & D. E. Abbott), p. 98. AFOSR/Lehigh University Workshop.
Hussain, A. K. M. F. & Reynolds, W. C. 1970 The mechanics of an organized wave in turbulent shear flow. J. Fluid Mech. 41, 241.Google Scholar
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
Schlichting, H. 1968 Boundary Layer Theory, 6th edn, p. 280. McGraw-Hill.
Sreenivasan, K. R., Antonia, R. A. & Britz, D. 1979 Local isotropy and large structures in a heated turbulent jet. J. Fluid Mech. 94, 745.Google Scholar
Subramanian, C. S. & Antonia, R. A. 1979 Some properties of the large scale structure in a slightly heated turbulent boundary layer. Proc. 2nd Int. Symp. on Turbulent Shear Flows, London, 4.18.
Thomas, A. S. W. & Brown, G. L. 1977 Large structure in a turbulent boundary layer. Proc. 6th Australasian Hydraulics & Fluid Mechanics Conf., Adelaide, p. 407.
Van atta, C. W. & Helland, K. N. 1980 Exploratory temperature tagging measurements of turbulent spots in a heated laminar boundary layer. J. Fluid Mech. 100, 243.Google Scholar
Willmarth, W. W. & Bogar, T. J. 1977 Survey and new measurements of turbulent structure near the wall. Phys. Fluids 20, S9.Google Scholar
Wygnanski, I. 1978 On the possible relationship between the transition process and the large coherent structures in turbulent boundary layers. In Coherent Structure of Turbulent Boundary Layers (ed. C. R. Smith & D. E. Abbott), p. 168. AFOSR/Lehigh University Workshop.
Wygnanski, I., Haritonidis, J. H. & Kaplan, R. E. 1979 On a Tollmien-Schlichting wave packet produced by a turbulent spot. J. Fluid Mech. 92, 505.Google Scholar
Wygnanski, I., Sokolov, M. & Friedman, D. 1976 On a turbulent ‘spot’ in a laminar boundary layer. J. Fluid Mech. 78, 785.Google Scholar
Zilberman, M., Wygnanski, I. & Kaplan, R. E. 1977 Transitional boundary layer spot in a fully turbulent environment. Phys. Fluids 20, S258.Google Scholar