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‘Stable’ density stratification as a catalyst for instability

Published online by Cambridge University Press:  19 April 2006

D. J. Acheson
D. J. Acheson*
Affiliation:
Jesus College, Oxford
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Abstract

A physical explanation is suggested for how the instability of certain fluid systems may be provoked by the addition of a ‘bottom-heavy’ density gradient. It is shown that in all the recent examples of this behaviour the stratification shifts the oscillation frequency at the marginal state towards the diffusion rate associated with the driving mechanism for the instability, and this allows a more effective release of the available energy. When the driving mechanism is an adverse temperature gradient, for example, the frequency shift induced by a bottom-heavy solute distribution can increase the temperature change that a vertically-displaced fluid parcel acquires during each halfcycle, thereby enhancing the thermal buoyancy forces which drive the instability.

Information

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 96 , Issue 4 , 27 February 1980 , pp. 723 - 733
Copyright
Copyright © 1980 Cambridge University Press

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References

Acheson, D. J. 1978a Phil. Trans. Roy. Soc. A 289, 459–500.Google Scholar
Acheson, D. J. 1978b In Rotating Fluids in Geophysics. (ed. Roberts, P. H. & Soward, A. M.), pp. 315–349. Academic.Google Scholar
Acheson, D. J. 1979a Solar Phys. 62, 23–50.10.1007/BF00150129CrossRefGoogle Scholar
Acheson, D. J. 1979b Astrophys. Space Sci. (in press).Google Scholar
Acheson, D. J. 1979a To be published.Google Scholar
Acheson, D. J. & Gibbons, M. P. 1978a J. Fluid Mech. 85, 743–757.10.1017/S0022112078000907CrossRefGoogle Scholar
Acheson, D. J. & Gibbons, M. P. 1978b Appendix to Acheson 1978a.Google Scholar
Chandrasekhar, S. 1961 Hydrodynamic and Hydromagnetic Stability. Clarendon.Google Scholar
Davey, A. & Reid, W. H. 1977 J. Fluid Mech. 80, 527–534.10.1017/S0022112077001827CrossRefGoogle Scholar
Fearn, D. 1979 Geophys. Astrophys. Fluid Dyn. (in press).Google Scholar
Griffiths, R. W. 1979 J. Fluid Mech. 92, 659–670.10.1017/S0022112079000811CrossRefGoogle Scholar
Howard, L. N. & Maslowe, S. A. 1973 Boundary Layer Met. 4, 511–523.10.1007/BF02265252CrossRefGoogle Scholar
Masuda, A. 1978 J. Ocean. Soc. Japan 34, 8–16.10.1007/BF02109611CrossRefGoogle Scholar
Pearlstein, A. J. 1977 Effect of rotation on the stability of a doubly diffusive fluid layer. M.Sc. thesis, University of California, Los Angeles.Google Scholar
Pearlstein, A. J. 1979 Submitted to J. Fluid Mech.Google Scholar
Roberts, P. H. 1978 In Rotating Fluids in Geophysics (ed. Roberts, P. H. & Soward, A. M.), pp. 420–436. Academic.Google Scholar
Roberts, P. H. & Loper, D. E. 1979 J. Fluid Mech. 90, 641–668.10.1017/S0022112079002469CrossRefGoogle Scholar
Roberts, P. H. & Stewartson, K. 1977 Astr. Nachr. 298, 311–318.10.1002/asna.19772980607CrossRefGoogle Scholar
Soward, A. M. 1979 J. Fluid Mech. 90, 669–684.10.1017/S0022112079002470CrossRefGoogle Scholar
Turner, J. S. 1974 Ann. Rev. Fluid Mech. 6, 37–56.10.1146/annurev.fl.06.010174.000345CrossRefGoogle Scholar