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Features of a separating turbulent boundary layer in the vicinity of separation

Published online by Cambridge University Press:  11 April 2006

Roger L. Simpson ,
J. H. Strickland  and
P. W. Barr
Roger L. Simpson
Affiliation:
Department of Civil and Mechanical Engineering, Southern Methodist University, Dallas, Texas 75275
J. H. Strickland
Affiliation:
Department of Civil and Mechanical Engineering, Southern Methodist University, Dallas, Texas 75275 Present address: Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas.
P. W. Barr
Affiliation:
Department of Civil and Mechanical Engineering, Southern Methodist University, Dallas, Texas 75275
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Abstract

Measurements of a separating two-dimensional incompressible boundary layer with an airfoil-type pressure distribution are reported. Unique mean and fluctuation velocity measurements and the distribution of the fraction of the time γp during which the flow moves downstream were obtained in the separated region using a directionally sensitive laser anemometer. Linearized hot-film anemometer measurements of mean velocities, turbulent shearing stress and intensities, eddy speeds, spectra and dissipation were made for γp > 0·8. The wall shearing stress, bursting frequencies, wall speed and spanwise structure were obtained using flush-surface hot-film sensors. The turbulent/non-turbulent interfacial intermittency γ and the frequency of passage of turbulent bulges were determined using smoke as a turbulence marker and the laser anemometer system for illumination and signal detection.

Upstream of separation the velocity profile correlations of Perry & Schofield (1973) are supported within the uncertainty of the data. Normal-stress effects are very important, influencing $-\overline{uv}/\overline{q^2} $ and the dissipation length correlations, and directly providing sizable terms in the momentum and turbulence energy equations. The criteria of Sandborn for turbulent separation and fully developed separation are found to hold. Downstream of separation there is apparent similarity of $\overline{u^2}$, U and γp throughout the shear flow. The passive low velocity backflow near the wall apparently just serves to satisfy continuity requirements after the energetic outer-region flow has deflected away from the wall upon separation.

The wall bursting frequency nA scales on outer velocity and length scales, with U∞/δnA ≈ 10, or about twice the value observed for zero-pressure-gradient flows. The non-dimensional spanwise spacing of wall eddies is given approximately by the relation λzUM/v ≈ 100 upstream of separation, where $U_M = (- \overline{uv}_{\max})^{\frac{1}{2}}$. The speed of wall eddies is found to be about 14Uτ.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 79 , Issue 3 , 9 March 1977 , pp. 553 - 594
Copyright
© 1977 Cambridge University Press

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References

Bakewell, H. P. & Lumley, J. L. 1967 Phys. Fluids, 10, 1880.
Black, T. J. 1968 N.A.S.A. Current Rep. CR-888.
Bradbury, L. J. S. 1965 J. Fluid Mech. 23, 31–64.
Bradshaw, P. 1967a J. Fluid Mech. 29, 625–645.
Bradshaw, P. 1967b Nat. Phys. Lab. Aero. Rep. no. 1220.
Bradshaw, P. 1973 AGARD Rep. AGARD-AG-169.
Bradshaw, P., Ferriss, D. H. & Atwell, N. P. 1967 J. Fluid Mech. 28, 593–616.
Bradshaw, P., Ferriss, D. H. & Atwell, N. P. 1974 Imperial College Aero. Rep. no. 74–02 (revised version of Bradshaw et al. (1967) with K. Unsworth).
Brodkey, R. S., Hershey, H. C. & Corino, E. R. 1969 Symp. Turbulence in Liquids, Univ. Missouri-Rolla (ed. J. L. Zakin & G. Patterson), p. 129.
Champagne, F. & Sleicher, C. A. 1967 J. Fluid Mech. 28, 177–182.
Coles, D. & Hirst, E. 1969 Comp. Turbulent Boundary Layers. 1968 AFOSR–IFP Stanford Conf., vol. 2. Data Compilation.
Collins, M. A. & Simpson, R. L. 1976 Dept. Civil Engng, Southern Methodist Univ., Rep. WR–4.
Corino, E. R. & Brodkey, R. S. 1969 J. Fluid Mech. 37, 1–30.
Echols, W. H. & Young, J. A. 1963 Naval Res. Lab. Rep. no. 5929.
Fiedler, H. & Head, M. R. 1966 J. Fluid Mech. 25, 719–735.
Freymuth, P. 1967 Rev. Sci. Inst. 38, 677–681.
Gupta, A. K., Laufer, J. & Kaplan, R. E. 1971 J. Fluid Mech. 50, 493–512.
Halleen, R. M. 1964 Thermosci. Div., Dept. Mech. Engng., Stanford Univ., Rep. MD–11.
Kim, H. T., Kline, S. J. & Reynolds, W. C. 1971 J. Fluid Mech. 50, 133–160.
Klebanoff, P. 1955 N.A.C.A. Rep. no. 1247.
Kline, S. J. & McClintock, F. A. 1953 Mech. Engng, 75, 3–8.
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 J. Fluid Mech. 30, 741–773.
Kovasznay, L. S. G., Kibens, V. & Blackwelder, R. E. 1970 J. Fluid Mech. 41, 238–325.
McDonald, H. 1969 J. Fluid Mech. 35, 311–336.
Mazumder, M. K., Hoyle, B. D. & Kirsch, K. J. 1974 Proc. 2nd Int. Workshop Laser Velocimetry, vol. 2 (ed. H. D. Thompson and W. H. Stevenson), pp. 234–269. Purdue Univ. School Mech. Engng.
Meek, R. L. 1972 A.I.Ch.E. J. 18, 854–855.
Morrison, W. R. B., Bullock, K. J. & Kronauer, R. E. 1971 J. Fluid Mech. 47, 639–656.
Newman, B. G. 1951 Dept. Supply Aero. Res. Consultative Comm., Univ. of Sydney, Rep. ACA-53.
Perry, A. E. & Schofield, W. H. 1973 Phys. Fluids, 16, 2068–2074.
Rao, K. N., Narasimha, R. & Badri Narayanan, M. A. 1971 J. Fluid Mech. 48, 339–352.
Rotta, J. C. 1962 Progress in Aeronautical Sciences, vol. 2, pp. 1–219. Pergamon.
Samuel, A. E. & Joubert, P. N. 1974 J. Fluid Mech. 66, 481–505.
Sandborn, V. A. & Kline, S. J. 1961 J. Basic Engng, Trans. A.S.M.E. 83, 317–327.
Sandborn, V. A. & Liu, C. Y. 1968 J. Fluid Mech. 32, 293–304.
Schubauer, G. B. & Klebanoff, P. S. 1951 N.A.C.A. Rep. no. 1030.
Simpson, R. L. 1975 Phys. Fluids, 18, 1068–1069.
Simpson, R. L. 1976 A.I.A.A. J. 14, 124–126.
Simpson, R. L. & Barr, P. W. 1974 Proc. 2nd Int. Workshop on Laser Velocimetry (ed. W. H. Stevenson & H. D. Thompson). Purdue Univ. School Mech. Engng.
Simpson, R. L. & Barr, P. W. 1975 Rev. Sci. Inst., 46, 835–837.
Simpson, R. L., Strickland, J. H. & Barr, P. W. 1973 Symp. Turbulence in Liquids, Univ. Missouri-Rolla (ed. J. L. Zakin & G. Patterson), pp. 151–171.
Simpson, R. L., Strickland, J. H. & Barr, P. W. 1974 Thermal Fluid Sci. Center, Southern Methodist Univ., Rep. WT–3.
So, R. M. C. & Mellor, G. L. 1973 J. Fluid Mech. 60, 43–62.
Sovran, G. 1969 Comp. Turbulent Boundary Layers. 1968 AFOSR–IFP Stanford Conf., vol. 1 (ed. Kline et al.), pp. 447–455.
Spangenberg, W. G., Rowland, W. R. & Mease, N. E. 1967 Fluid Mechanics of Internal Flow (ed. G. Sovran), pp. 110–150. Elsevier.
Strickland, J. H. & Simpson, R. L. 1973 Thermal Fluid Sci. Center, Southern Methodist Univ., Rep. WT–2.
Strickland, J. H. & Simpson, R. L. 1975 Phys. Fluids, 18, 306–308.
Taylor, G. I. 1938 Proc. Roy. Soc. A 164, 476–490.
Townsend, A. A. 1962 J. Fluid Mech. 12, 536–554.
Willmarth, W. W. 1975 Adv. Appl. Mech. 15, 159–254.
Wygnanski, I. & Fiedler, H. E. 1970 J. Fluid Mech. 41, 327–361.
Wyngaard, J. C. 1969 J. Sci. Inst. 2, 983–987.