Skip to main content Accessibility help

‘Stable’ density stratification as a catalyst for instability

  • D. J. Acheson (a1)


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.



Hide All
Acheson, D. J. 1978a Phil. Trans. Roy. Soc. A 289, 459500.
Acheson, D. J. 1978b In Rotating Fluids in Geophysics. (ed. P. H. Roberts & A. M. Soward), pp. 315349. Academic.
Acheson, D. J. 1979a Solar Phys. 62, 2350.
Acheson, D. J. 1979b Astrophys. Space Sci. (in press).
Acheson, D. J. 1979a To be published.
Acheson, D. J. & Gibbons, M. P. 1978a J. Fluid Mech. 85, 743757.
Acheson, D. J. & Gibbons, M. P. 1978b Appendix to Acheson 1978a.
Chandrasekhar, S. 1961 Hydrodynamic and Hydromagnetic Stability. Clarendon.
Davey, A. & Reid, W. H. 1977 J. Fluid Mech. 80, 527534.
Fearn, D. 1979 Geophys. Astrophys. Fluid Dyn. (in press).
Griffiths, R. W. 1979 J. Fluid Mech. 92, 659670.
Howard, L. N. & Maslowe, S. A. 1973 Boundary Layer Met. 4, 511523.
Masuda, A. 1978 J. Ocean. Soc. Japan 34, 816.
Pearlstein, A. J. 1977 Effect of rotation on the stability of a doubly diffusive fluid layer. M.Sc. thesis, University of California, Los Angeles.
Pearlstein, A. J. 1979 Submitted to J. Fluid Mech.
Roberts, P. H. 1978 In Rotating Fluids in Geophysics (ed. P. H. Roberts & A. M. Soward), pp. 420436. Academic.
Roberts, P. H. & Loper, D. E. 1979 J. Fluid Mech. 90, 641668.
Roberts, P. H. & Stewartson, K. 1977 Astr. Nachr. 298, 311318.
Soward, A. M. 1979 J. Fluid Mech. 90, 669684.
Turner, J. S. 1974 Ann. Rev. Fluid Mech. 6, 3756.
MathJax is a JavaScript display engine for mathematics. For more information see

‘Stable’ density stratification as a catalyst for instability

  • D. J. Acheson (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed