Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-10T06:31:07.916Z Has data issue: false hasContentIssue false

Experiments on the fine structure of turbulence

Published online by Cambridge University Press:  11 April 2006

M. A. Badri Narayanan
Affiliation:
Department of Aeronautical Engineering, Indian Institute of Science, Bangalore 560012
S. Rajagopalan
Affiliation:
Department of Aeronautical Engineering, Indian Institute of Science, Bangalore 560012
R. Narasimha
Affiliation:
Department of Aeronautical Engineering, Indian Institute of Science, Bangalore 560012

Abstract

Investigations have been carried out of some aspects of the fine-scale structure of turbulence in grid flows, in boundary layers in a zero pressure gradient and in a boundary layer in a strong favourable pressure gradient leading to relaminarization. Using a narrow-band filter with suitable mid-band frequencies, the properties of the fine-scale structure (appearing as high frequency pulses in the filtered signal) were analysed using the variable discriminator level technique employed earlier by Rao, Narasimha & Badri Narayanan (1971). It was found that, irrespective of the type of flow, the characteristic pulse frequency (say Np) defined by Rao et al. was about 0·6 times the frequency of the zero crossings.

It was also found that, over the small range of Reynolds numbers tested, the ratio of the width of the fine-scale regions to the Kolmogorov scale increased linearly with Reynolds number in grid turbulence as well as in flat-plate boundarylayer flow. Nearly lognormal distributions were exhibited by this ratio as well as by the interval between successive zero crossings.

The values of Np and of the zero-crossing rate were found to be nearly constant across the boundary layer, except towards its outer edge and very near the wall. In the zero-pressure-gradient boundary-layer flow, very near the wall the high frequency pulses were found to occur mostly when the longitudinal velocity fluctuation u was positive (i.e. above the mean), whereas in the outer part of the boundary layer the pulses more often occurred when u was negative. During acceleration this correlation between the fine-scale motion and the sign of u was less marked.

Type
Research Article
Copyright
© 1977 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. 1973 Phys. Fluids, 16, 1198.
Badri Narayanan, M. A. & Ramjee, V. 1969 J. Fluid Mech. 35, 225.
Badri Narayanan, M. A., Rajagopalan, S. & Narasimha, R. 1974 Dept. Aero. Engng, Indian Inst. Sci. Rep. 74 FM 15.
Badri Narayanan, M. A., Rao, K. N. & Narasimha, R. 1971 Proc. 4th Austr. Conf. Hydraul. Fluid Mech., p. 73.
Batchelor, G. K. & Townsend, A. A. 1948 Proc. Roy. Soc. A 193, 539.
Batchelor, G. K. & Townsend, A. A. 1949 Proc. Roy. Soc. A 199, 238.
Blackwelder, R. F. & Kovasznay, L. S. G. 1970 Interim Tech. Rep., Dept. Mech., John Hopkins Univ.
Brodkey, R. S., Wallace, J. M. & Eckelmann, H. 1974 J. Fluid Mech. 63, 209.
Coles, D. 1962 Rand Corp. Rep. R-403-PR.
Corino, E. R. & Brodkey, R. S. 1969 J. Fluid Mech. 37, 1.
Corrsin, S. 1962 Phys. Fluids, 5, 1301.
Falco, R. E. 1974 A.I.A.A. 12th Aero. Sci. Meeting, Washington, paper 74–79.
Grant, H. C., Stewart, R. W. & Moilliet, A. 1962 J. Fluid Mech. 12, 241.
Kennedy, D. A. & Corrsin, S. 1961 J. Fluid Mech. 10, 366.
Klebanoff, P. S. 1954 N.A.C.A. Tech. Note, no. 3178.
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 J. Fluid Mech. 30, 741.
Kolmogorov, A. N. 1941 C.R. Acad. Sci. (Doklady) U.S.S.R. 30, 301.
Kuo, A. S. & Corrsin, S. 1971 J. Fluid Mech. 50, 285.
Kuo, A. S. & Corrsin, S. 1972 J. Fluid Mech. 56, 447.
Laufer, J. 1951 N.A.C.A. Tech. Note, no. 1174.
Liepmann, H. W., Laufer, J. & Liepmann, K. 1951 N.A.C.A. Tech. Note, no. 2473.
Lu, S. S. & Willmarth, W. W. 1973 J. Fluid Mech. 60, 481.
Rao, K. N., Narasimha, R. & Badri Narayanan, M. A. 1971 J. Fluid Mech. 48, 339.
Sabot, J. & Comte-Bellot, G. 1976 J. Fluid Mech. 74, 767796.
Sandborn, V. A. 1959 J. Fluid Mech. 6, 221.
Schraub, F. A. & Kline, S. J. 1965 Dept. Mech. Engng, Stanford Univ. Rep. MD-12.
Tennekes, H. 1968 Phys. Fluids, 11, 669.
Townsend, A. A. 1956 The Structure of Turbulent Shear Flow. Cambridge University Press.
Willmarth, W. W. & Lu, S. S. 1972 J. Fluid Mech. 55, 65.
Wyngaard, J. C. & Tennekes, H. 1970 Phys. Fluids, 13, 1962.