In this paper we present a rather personal view of the important developments in double-diffusive convection, a subject whose evolution has been the result of a close interaction between theoreticians, laboratory experimenters and sea-going oceano-graphers. More recently, applications in astrophysics, engineering and geology have become apparent. In the final section we attempt to draw some general conclusions and suggest that further progress will again depend on a close collaboration between fluid dynamicists and other scientists.

Double-diffusive convection

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Dynamic theory of quasilinear parabolic systems: III. Global existence

We have employed a laser‐beam‐deflection technique to measure the Soret coefficient of ethanol/water solutions with ethanol weight fractions ranging from 0.02 to 0.39, over the temperature range 10 to 40 °C. This technique also allows precise determination of the mass‐diffusion coefficient and of the index of refraction. These results have permitted us to obtain a quantitative understanding of recent experiments on oscillatory traveling‐wave convection in binary fluid mixtures.

Optical measurement of the Soret coefficient of ethanol/water solutions

Stability analysis of soret-driven double-diffusive convection of Maxwell fluid in a porous medium

Quasilinear parabolic systems under nonlinear boundary conditions

The suggestion made by the authors in a previous paper (Hurle & Jakeman 1969) that the Soret effect could give rise to overstable solutions of the thermosolutal Rayleigh–Jeffreys problem is investigated theoretically and experimentally.Oscillatory instability is shown to occur in initially homogeneous layers of water-methanol mixtures when they are heated from below. This instability triggers a finite-amplitude steady mode. The magnitude and sign of the Soret coefficient was changed by varying the composition of the mixture; as predicted, overstable modes were observed when the sign of the coefficient was such as to produce a stabilizing contribution to the density gradient. The observed critical Rayleigh numbers and temporal frequencies are consistent with theory.

D. T. J. Hurle

Papers

Soret-driven thermosolutal convection