Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-19T15:11:26.388Z Has data issue: false hasContentIssue false
  • English
  • Français

An experimental investigation of a turbulent shear flow with separation, reverse flow, and reattachment

Published online by Cambridge University Press:  21 April 2006

R. Ruderich  and
H. H. Fernholz
R. Ruderich
Affiliation:
Hermann-Föttinger-Institut, Teohnische Universitát, Berlin
H. H. Fernholz
Affiliation:
Hermann-Föttinger-Institut, Teohnische Universitát, Berlin
Get access Rights & Permissions [Opens in a new window]

Abstract

Experiments were performed in the highly turbulent and disturbed flow over a bluff plate with a long splitter plate in its plane of symmetry. The flow separates at the sharp bevelled edge of the bluff plate, forms a free shear layer on top of the reverse-flow region which is bounded on its other side by the splitter plate, and reattaches on the splitter plate over a narrow region curved in spanwise direction. Downstream of reattachment the shear flow adjusts slowly to the wall boundary conditions.

Measurements of mean velocity, Reynolds-shear-stress and Reynolds-normal-stress distributions were carried out by hot-wire and pulsed-wire anemometry. The latter technique was used in those regions of the flow where reverse flow occurred or where the flow was highly turbulent. Spectra and integral lengthscales were measured to investigate the state and structure of the flow. The large-eddy structure in the inner region of the flow had lengthscales in the two cross-stream directions which were approximately equal, indicating a fast break-up of spanwise structures just downstream from separation.

Mean and fluctuating quantities showed a self-similar behaviour in a short region upstream of reattachment and ‘profile similarity’ in the separated shear layer and along the splitter plate downstream from reattachment. Probability-density distributions of skin friction were measured and used to calculate mean and fluctuating values. No flapping of the reattaching shear layer could be observed. Pulsed-wire measurements revealed that the logarithmic law of the wall does not hold either in the reverse-flow region or in a region about half the length of the bubble downstream from reattachment.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 163 , February 1986 , pp. 283 - 322
Copyright
© 1986 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

Arie, M. & Rouse, H. 1956 Experiments on two-dimensional flow over a normal wall. J. Fluid Mech. 1, 129–141.Google Scholar
Bradbury, L. J. S. & Castro, I. P. 1971 A pulsed-wire technique for velocity measurements in highly turbulent flows. J. Fluid Mech. 49, 657–691.Google Scholar
Bradshaw, P. & Wong, F. Y. F. 1972 The reattachment and relaxation of a turbulent shear layer. J. Fluid Mech. 52, 113–135.Google Scholar
Brown, G. L. & Roshko, A. 1974 On density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64, 775–816.Google Scholar
Castro, I. P. & Dianat, M. 1983 Surface flow patterns on rectangular bodies in thick boundary layers. J. Wind Engng Indust. Aerodyn. 11, 107–119.Google Scholar
Chandrasuda, C. & Bradshaw, P. 1981 Turbulence structure of a reattaching mixing layer. J. Fluid Mech. 110, 171–194.Google Scholar
Cherry, N. J., Hillier, R. & Latour, M. E. M. P. 1984 Unsteady measurements in a separated and reattaching flow. J. Fluid Mech. 144, 13–46.Google Scholar
Dahm, A. & Vagt, J. D. 1977 Entwicklung und Herstellung interferenzarmer Hitzdrahtsonden. HFI Inst. 01/77.Google Scholar
De Brederode, V. & Bhadshaw, P. 1972 Three-dimensional flow in nominally two-dimensional separation bubbles. I. Flow behind a rearward-facing step. Imperial College Aero Rep. 72–19.Google Scholar
De Brederode, V. A. S. L. 1975 Three-dimensional effects in nominally two-dimensional flow. Ph.D. thesis, Imperial College, London University
Dengel, P., Fernholz, H. H. & Vagt, J.-D. 1982 Turbulent and mean flow measurements in an incompressible axisymmetric boundary layer with incipient separation. Turbulent Shear Flows 3 (ed. Bradbury el al.). Springer.
Eaton, J. K. & Johnston, J. P. 1980 Turbulent flow reattachment. An experimental study of the flow and structure behind a backward-facing step. Rep. MD-39. Stanford University.
Eaton, J. K. & Johnston, J. P. 1981 A review of research on subsonic turbulent flow reattachment. AIAA J. 19, 1093–1100.Google Scholar
Fernholz, H. H., Graham, J. M. R. & Vagt, J.-D. 1982 A wind tunnel for unsteady turbulent shear flows: design and flow calculation. Z. Flugwiss. Weltraumforschung 6, 408–416.Google Scholar
Fernholz, H. H. & Vagt, J.-D. 1981 Turbulence measurements in an adverse-pressure-gradient three-dimensional turbulent oundary layer along a circular cylinder. J. Fluid Mech. 1ll, 233–269.Google Scholar
Froebel, E. & Vagt, J.-D. 1974 Ein automatisch abgleichendes FluUssigkeitsmanometer mit digitaler Anzeige. DLR-FB 74–40.Google Scholar
Gence, J. N. & Mathieu, J. 1980 The return to isotropy of homogeneous turbulence having been submitted to two successive plane strains. J. Fluid Mech. 101, 555–566.Google Scholar
Ginder, R. B. & Bradbury, L. J. S. 1973 Preliminary investigation of a pulsed-gauge technique for skin friction measurements in highly turbulent flow. ARC Paper 34448.
Hillieh, R. 1978 Further measurements in a separated and reattaching flow. Imperial College London, Dept of Aeronautics.
Hillier, R. & Cherry, N. J. 1981 The effects of stream turbulence on separation bubbles. J. Wind Engng Indust. Aero. 8, 49–58.Google Scholar
Hillier, R., Latour, M. E. M. P. & Cherry, N. J. 1983 Unsteady measurements in separated– and reattaching flows. 4th Turbulent Shear Flow Conf. Karlsruhe.
Kiya, M., Sasaki, K. & Arie, M. 1982 Discrete vortex simulation of a turbulent separation bubble. J. Fluid Mech. 120, 219–244.Google Scholar
Kiya, M. & Sasaki, K. 1983 Structure of a turbulent separation bubble. J. Fluid Mech. 137, 83–113.Google Scholar
Kottke, V. 1983 StroUmung, Stoff-, WaUrme- und ImpuUlsubertragung in lokalen AbloUsegebieten. Fortachrittsberichte VDI-Z. Reihe 7 Nr. 77.Google Scholar
Kreplin, H. P. 1976 Experimentelle Untersuchungen der LaUngsschwankungen und der wand- parallelen Querschwankungen der Geschwindigkeit in einer turbulenten KanalstroUmung. DFVLR-Verlag u. MPI-GoUttingen.
Mensing, P. & Fiedler, H. 1980 Eine Methode zur Sichtbarmachung von hochturbulenten LuftstroUmungen mit grossen Reynolds-Zahlen. Z. Flugwiss. Weltraumforschung 4, 366–368.Google Scholar
Patel, V. C. 1965 Calibration of the Preston tube and limitations on its use in pressure gradients. J. Fluid Mech. 23, 185–208.Google Scholar
Pui, N. K. & Gartshore, I. S. 1979 Measurements of the growth rate and structure in plane turbulent mixing layers. J. Fluid Mech. 91, 111–130.Google Scholar
Ranga Rajxt, K. G. & Garde, R. J. 1970 Resistance of an inclined plate placed on a plane boundary in two-dimensional flow. Trans. ASMS D: J. Basic Engng 92, 21–31Google Scholar
Rogers, B. K. & Head, M. R. 1969 Measurements of three-dimensional boundary layers. J. R. Aeronaut. Soc. 73, 796–798.Google Scholar
Roshko, A. & Lau, J. C. 1965 Some observations on transition and reattachment of a free shear layer in incompressible flow. In Proc. 1965 Heat Transfer and Fluid Mech. Inst.
Ruderich, R. & Fernholz, H. H. 1983 An experimental investigation of the turbulent shear flow downstream of a normal flat plate with a long splitter plate-modification of a model. 4th Turbulent Shear Flow Conf., Karlsruhe.
Simpson, R. L. 1976 Interpreting laser and hot-film anemometer signals in a separating boundary layer. AIAA J. 14, 124–126.Google Scholar
Smits, A. J. 1980 A visual study of a separation bubble. In Intl Symp. on Flow Visualization, Bochum.
Smits, A. J. 1982 Scaling parameters for a time-averaged separation bubble. Trans. ASMS I: J. Fluids Engng 104, 178–184Google Scholar
Stevenson, W. H., Thompson, H. D. & Craig, R. R. 1984 Laser velocimeter measurements in highly turbulent recirculating flows. Trans. ASMS I: J. Fluids Engng 106, 173–180Google Scholar
Tutu, N. K. & Chevray, R. 1975 Cross-wire anemometry in high turbulence. J. Fluid Mech. 71, 785–800.Google Scholar
Vagt, J.-D. 1979 Hot-wire probes in low speed flow. Prog. Aero. Sci. 18, 271–325.Google Scholar
Westphal, R. V., Johnston, J. P. & Eaton, J. K. 1984 Experimental study of flow reattachment in a single-sided sudden expansion. NASA Contractor Rep. 3765.Google Scholar
Wood, D. & Bradshaw, P. 1983 A turbulent mixing layer constrained by a solid surface. Part 1. Measurements before reaching the surface. J. Fluid Mech. 122, 57–89.Google Scholar
Wood, D. & Bradshaw, P. 1984 A turbulent mixing layer constrained by a solid surface. Part 2. Measurements in the wall-bounded flow. J. Fluid Mech. 139, 347–361.Google Scholar
Wygnanski, I. & Fiedler, H. E. 1970 The two-dimensional mixing region. J. Fluid Mech. 41, 327–361.Google Scholar