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The effect of a density difference on shear-layer instability

Published online by Cambridge University Press:  29 March 2006

Robert F. Davey  and
Anatol Roshko
Robert F. Davey
Affiliation:
California Institute of Technology, Pasadena
Anatol Roshko
Affiliation:
California Institute of Technology, Pasadena
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Abstract

Measurements of mass flow rate and mean density have been made in separated laminar boundary layers with large transverse density gradients. Two-dimensional shear layers were formed by exhausting a half-jet of one gas into a reservoir of another gas with a different molecular weight. Two freons with a density ratio of 1-98 and unusual properties which permitted the measurement of the mass flow rate with a single hot wire were used. A n analysis of the mass flow rate fluctuations showed that a negative density gradient (i.e. light gas flowing into heavy) increases the amplification rate of the instability oscillations and reduces the frequency and wave number. Opposite trends were observed when the density gradient was positive. These findings are in agreement with recent theoretical predictions.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 53 , Issue 3 , 13 June 1972 , pp. 523 - 543
Copyright
© 1972 Cambridge University Press

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References

Baker, R. L., Rozenman, T. & Weinstein, H. 1965 Stability of shear flow with density gradient and viscosity. N.A.S.A. Contractor Rep. CR 958.Google Scholar
Browand, F. K. 1966 An experimental investigation of the instability of an incompressible, separated shear layer. J. Fluid Mech., 26, 281.Google Scholar
Brown, G. L. & Rebollo, M. 1972 A probe to measure density. A.I.A.A. J. To be publishedGoogle Scholar
Collis, D. C. & Williams, M. J. 1959 Two-dimensional convection from heated wires at low Reynolds numbers. J. Fluid Mech., 6, 357.Google Scholar
Davey, R. F. 1971 Mass flow rate measurements in a heterogeneous medium A.I.A.A. J. 9, 1874.Google Scholar
Freymutr, P. 1966 On transition in a separated laminar boundary layer. J. Fluid Mech., 25, 683.Google Scholar
Gropenoiesser, H. 1969 Beitrag Bur Stabi1ita.t freier Grenzshichten in kompressiblen Medien. Deutsche Luftund Raumfahrt, Forsch. Ber. 69–25.Google Scholar
Landau, L. D. & Lifshitz, E. M. 1959 Fluid Mechanics. Addison-Wesley.
Maslowe, S. A. & Kelly, R. E. 1971 Inviscid instability of an unbounded heterogeneous shear layer. J. Fluid Mech., 48, 405.Google Scholar
Micealxe, A. 1970 The instability of free shear layers: a survey of the state of art. Deutsche Luft-und Raumfahrt, Mitt. 70-04.Google Scholar
Sato, H. 1956 Experimental investigation on the transition of a laminar separated layer. J. Phys. Soc. Japan, 11, 70Google Scholar
Sato, H. 1959 Further investigation on the transition of two-dimensional separated layer at subsonic speeds. J. Phys. Soc Japan, 14, 1797.Google Scholar
Way, J. & Libby, P. 1970 Hot-wire probes for measuring velocity and concentration in helium-air mixtures. A.I.A.A.J., 8, 976.Google Scholar