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Study of turbulent structure with hot wires smaller than the viscous length

Published online by Cambridge University Press:  20 April 2006

William W. Willmarth  and
Lalit K. Sharma
William W. Willmarth
Affiliation:
Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan 48109
Lalit K. Sharma
Affiliation:
Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan 48109 Present address: Rockwell Intl Rocketdyne Div., Canoga Park, California.
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Abstract

The small-scale structure of the streamwise velocity fluctuations in the wall region of a turbulent boundary layer is examined in a new wind-tunnel facility using hot-wires smaller than any previously constructed (typical dimensions: l = 25 μm, d = 0.5 μm). In the boundary layer in which the measurements were made, the ratio of the hot-wire length to the viscous length is 0.3. The turbulent intensity measured with the small hot wires is larger than that measured with longer wires owing to the better spatial resolution of the small wires. The velocity fluctuations measured by the small hot wires are also analysed to determine the burst frequency at two Reynolds numbers and at various distances from the wall. The dimensionless burst frequency does not depend on the Reynolds number when scaled with wall parameters. However, it increases with Reynolds number when scaled with outer variables. Velocity fluctuations measured by two hot wires, less than two viscous lengths apart, are analysed to reveal the small-scale features present during a burst and in the absence of a burst. The main conclusions are: (1) intermittent small-scale shear layers occur most frequently when bursts are present, less frequently just after a burst, and even less frequently just before a burst; and (2) on occasion the velocity gradient of the small-scale shear layers is as large as the mean-velocity gradient at the wall.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 142 , May 1984 , pp. 121 - 149
Copyright
© 1984 Cambridge University Press

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References

Betchov, R. 1952 Nonlinear theory of a hot-wire anemometer. NACA Tech. Memo. 1346.Google Scholar
Black, J. R. 1969 Electromigration - a brief survey and some recent results. IEEE Trans. on Electron Devices, ED 16, 338.Google Scholar
Blackwelder, R. F. & Haritonidis, J. H. 1983 The bursting frequency in turbulent boundary layers. J. Fluid Mech. 132, 87.Google Scholar
Blackwelder, R. F. & Kaplan, R. E. 1976 On the wall structure of the turbulent boundary layer. J. Fluid Mech. 76, 89.Google Scholar
Bull, M. & Thomas, A. S. W. 1976 High frequency wall-pressure fluctuations in turbulent boundary layers. Phys. Fluids 19, 597.Google Scholar
Chen, C. P. & Blackwelder, R. F. 1978 The large-scale motion in a turbulent boundary layer: a study using temperature contamination. J. Fluid Mech. 89, 1.Google Scholar
Coles, D. E. 1955 The law of the wall in turbulent shear flow. In 50 Jahre Grenzschichtforschung, p. 153. Vieweg.
Collis, D. C. & Williams, M. J. 1959 Two-dimensional convection from heated wires. J. Fluid Mech. 6, 357.Google Scholar
Corino, E. R. & Brodkey, R. S. 1969 A visual investigation of the wall region in turbulent flow. J. Fluid Mech. 37, 1.Google Scholar
Eckelmann, H. 1974 The structure of the viscous sublayer and the adjacent wall region in a turbulent channel flow. J. Fluid Mech. 65, 439.Google Scholar
Emmerling, R. 1973 The instantaneous structure of the wall pressure under a turbulent boundary layer flow. Max-Planck-Inst. Stromungsforsch. Rep. 97/1973.Google Scholar
Fage, F. A. & Townend, H. C. H. 1932 An examination of turbulent flow with an ultra-microscope. Proc. R. Soc. Lond. A 135, 656.Google Scholar
Gupta, A. K., Laufer, J. & Kaplan, R. E. 1971 Spatial structure in the viscous sublayer. J. Fluid Mech. 50, 493.Google Scholar
Hama, F. R., Long, J. D. & Hegarty, J. C. 1957 On transition from laminar to turbulent flow. J. Appl. Phys. 28, 388.Google Scholar
Hummel, R. E. & Breitling, R. M. 1971 On the direction of electromigration in thin silver, gold, and copper films. App. Phys. Lett. 18, 373.Google Scholar
Kastrinakis, E. G. 1977 Max-Planck-Inst. Strömungsforsch. Rep. 5/1977.
Kim, H. T., Kline, S. J. & Reynolds, W. C. 1971 The production of turbulence near a smooth wall in a turbulent boundary layer. J. Fluid Mech. 50, 133.Google Scholar
Klebanoff, P. S. 1954 Characteristics of turbulence in a boundary layer with zero pressure gradient. NACA Tech. Note 3178.Google Scholar
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 The structure of turbulent boundary layers. J. Fluid Mech. 30, 741.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, 305.Google Scholar
Kronauer, R. E. 1953 Survey of hot-wire theory and techniques, Div. Appl. Sci., Harvard Univ. (Pratt & Whitney Res.) Rep. 137.Google Scholar
Kreplin, H. P. & Eckelmann, H. 1979 Propagation of perturbations in the viscous sublayer and adjacent wall region. J. Fluid Mech. 95, 305.Google Scholar
Laufer, J. & Badri Narayanan, M. A. 1971 Mean period of the turbulent production mechanism in a turbulent boundary layer. Phys. Fluids 14, 182.Google Scholar
Lu, S. S. & Willmarth, W. W. 1972 Measurements of the structure of the Reynolds stress in a turbulent boundary layer. J. Fluid Mech. 60, 481.Google Scholar
Narahari Rao, K., Narasimha, R. & Badri Narayanan, M. A. 1971 The bursting phenomena in a turbulent boundary layer. J. Fluid Mech. 48, 339.Google Scholar
Sharma, L. 1980 Study of turbulent structure with hot-wires smaller than the viscous length. Ph.D. thesis, University of Michigan.
Willmarth, W. W. & Bogar, T. J. 1977 Survey and new measurements of turbulent structure near the wall. Phys. Fluids Suppl. 20, S9.Google Scholar
Willmarth, W. W., Winkel, R. E., Sharma, L. K. & Bogar, T. J. 1976 Axially symmetric turbulent boundary layers on cylinders. J. Fluid Mech. 76, 35.Google Scholar
Wills, J. A. B. 1962 The correction of hot-wire readings for proximity to a solid boundary. J. Fluid Mech. 12, 388.Google Scholar