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Unsteady separation in a boundary layer produced by an impinging jet

Published online by Cambridge University Press:  20 April 2006

Norbert Didden  and
Chih-Ming Ho
Norbert Didden
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, California, 90089-1454 Present address: Institut für Meereskunde an der Universität Kiel, 23 Kiel 1, F. R. Germany.
Chih-Ming Ho
Affiliation:
Department of Aerospace Engineering, University of Southern California, Los Angeles, California, 90089-1454
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Abstract

A vortex-induced unsteady separation was investigated experimentally in the laminar boundary layer produced by an axisymmetric jet impinging normally onto a flat plate. By forcing the air jet, primary ring vortices were periodically generated in the jet shear layer. Phase-locked flow visualization showed that the wall-jet boundary layer separated periodically and evolved into a secondary vortex counter rotating with respect to the primary vortex. The unsteady separation is induced by the primary vortex and moves downstream in the radial mean-flow direction. Phase-averaged hot-wire measurements using a parallel-wire sensor in the vicinity of the unsteady separation provided data for locating the onset of separation in space and time. The data revealed that the unsteady separation originated from a local shear layer which was initiated by the unsteady adverse pressure gradient produced by the primary vortex.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 160 , November 1985 , pp. 235 - 256
Copyright
© 1985 Cambridge University Press

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References

Brown, G. L. & Roshko, A. 1974 On density effects and large structure in turbulent mixing layers. J. Fluid Mech. 64, 775–816.Google Scholar
Cebeci, T. 1982 Unsteady separation. In Numerical and Physical Aspects of Aerodynamic Flows (ed. T. Cebeci), pp. 265–77. Springer.
Cerra, A. W. & Smith, C. R. 1980 Experimental observation of the interaction of a vortex ring with a flat plate. Bull. Amer. Phys. Soc. 25, 1092.Google Scholar
Cousteix, J., Houdeville, R. & Javelle, J. 1981 Response of a turbulent boundary layer to a pulsation of the external flow with and without adverse pressure gradient. In Unsteady Turbulent Shear Flows (ed. R. Michel, J. Cousteix & R. Houdeville), pp. 120–144. Springer.
Despart, R. A. & Miller, J. A. 1971 Separation in oscillating laminar boundary-layer flows. J. Fluid Mech. 47, 21–31.Google Scholar
Didden, N. 1977 Untersuchung laminarer, instabiler Ringwirbel mittels Laser-Doppler-Anemometrie. Mitt. aus dem MPI für Strömungsforschung und der AVANR. 64 Göttingen.
Doligalski, T. L. 1980 The influence of vortex motion on wall boundary layers. Ph.D. Thesis, Lehigh University, Penn. U.S.A.
Gutmark, E. & Ho, C. M. 1983 On the preferred modes and the spreading rates of jets. Phys. Fluids 26, 2932–2938.Google Scholar
Harvery, J. K. & Perry, F. J. 1971 Flow field produced by trailing vortices in the vicinity of the ground. AIAA J. 9, 1659–1660.Google Scholar
Ho, C. M. 1983 An alternative look at the unsteady separation phenomenon. Recent Advances in Aerodynamics (ed. A. Krothapalli & C. A. Smith), pp. 165–178. Springer.
Ho, C. M. & Huerre, P. 1984 Perturbed free shear layers. Ann. Rev. Fluid Mech. 16, 365–424.Google Scholar
Ho, C. M. & Nosseir, N. S. 1981 Dynamics of an impinging jet. Part 1. The feedback phenomenon. J. Fluid Mech. 105, 119–142.Google Scholar
Homa, J. & Rockwell, D. 1983 Vortex–body interaction. Bull Am. Phys. Soc. 28, 1365.Google Scholar
Koromilas, C. A. & Telionis, D. P. 1980 Unsteady laminar separation: an experimental study. J. Fluid Mech. 97, 347–384.Google Scholar
Liang, S., Falco, R. E. & Bartholomew, R. W. 1983 Vortex ring/moving wall interactions: experiments and numerical modelling. Bull. Am. Phys. Soc. 28, 1397.Google Scholar
Magarvey, R. H. & Mclatchy, C. S. 1964 The disintegration of vortex rings. Can. J. Phys. 42, 684–689.Google Scholar
Mccroskey, W. J., Carr, L. W. & Mcalister, K. W. 1975 Dynamic stall experiments on oscillating airfoils. AIAA Paper No. 75–125.
Moore, F. K. 1985 On the separation of the unsteady laminar boundary layer. In Boundary-Layer Research (ed. H. G. Gortler), pp. 296–310. Springer.
Nishioka, M., Asai, M. & Iida, S. 1980 An experimental investigation of the secondary instability. In Laminar Turbulent Transition (ed. R. Eppler & H. Fasel), pp. 37–46. Springer.
Parikh, P. G., Reynolds, W. C., Jayaraman, R. & Carr, L. W. 1981 Dynamic behaviour of an unsteady turbulent boundary layer. In Unsteady Turbulent Shear Flows (ed. R. Michel, J. Cousteix & R. Houdeville), pp. 35–46. Springer.
Prandtl, L. 1904 Über Flüssigkeitsbewegung bei sehr kleiner Reibung. In Proc. III Intl Math. Congr. Heidelberg, pp. 484–491.
Rott, N. 1956 Unsteady viscous flow in the vicinity of a stagnation point. Q. Appl. Maths 13, 444–451.Google Scholar
Schneider, P. E. M. 1980 Sekundärwirbelbildung bei Ringwirbeln und in Freistrahlen. Z. Flugwiss. 4, 307–318.Google Scholar
Sears, W. R. 1956 Some recent developments in airfoil theory. J. Aero. Sci. 23, 490–499.Google Scholar
Sears, W. R. & Telionis, D. P. 1971 Unsteady boundary layer separation. In IUTAM Symp. on Recent Research on Unsteady Boundary Layers (ed. E. A. Eichelbrenner), vol. 1, pp. 404–447.
Simpson, R. L. 1981 A review of some phenomena in turbulent flow separation. Trans. ASME I: J. Fluids Engng 103, 520–533.Google Scholar
Tang, Y. P. & Rockwell, D. 1983 Instantaneous pressure fields at a corner associated with vortex impingement. J. Fluid Mech. 126, 187–204.Google Scholar
Telionis, D. P. 1981 Unsteady Viscous Flows. Springer.
Van Dommelen, L. L. & Shen, S. F. 1982 The genesis of separation. In Numerical and Physical Aspects of Aerodynamic Flows (ed. T. Cebeci), pp. 293–311. Springer.
Wang, K. C. 1979 Unsteady boundary layer separation. Martin MarietaLab. Rep. TR-79-16C.
Walker, J. D. A. 1978 The boundary layer due to rectilinear vortex. Proc. R. Soc. Lond. A 359, 167–188.Google Scholar
Walker, T. B. & Bullock, K. J. 1972 Measurement of longitudinal and normal velocity fluctuations by sensing the temperature downstream of a hot wire. J. Phys. E: Sci. Instrum. 5, 1173–1178.Google Scholar
Weidman, P. D. & Browand, F. K. 1975 Analysis of a simple circuit for constant temperature anemometry. J. Phys. E: Sci. Instrum. 8, 553–560.Google Scholar
Widnall, S. E. & Tsai, C. Y. 1977 The instability of the thin vortex ring of constant vorticity. Phil. Trans. R. Soc. Lond. A 287, 273–305.Google Scholar
Williams, J. C. 1977 Incompressible boundary -layer separation. Ann. Rev. Fluid Mech. 9, 113–144.Google Scholar