We have studied the different scenarios for layered structures to form or be destroyed in time-dependent, double-diffusive convection for an infinite Prandtl number fluid. We have concentrated on the subcritical diffusive and finger regimes and examined the thermal-chemical evolution as applied to magma chambers. Both cooling from the top and side boundary conditions have also been examined. Subcritical double-diffusive convection yields the most favorable conditions for layering. A sufficiently high chemical buoyancy ratio keeps the layering intact and yields a small Nusselt number. Double-diffusive convection in the subcritical regime can lead to layering from an initially unlayered state. There are no evidences for layering in the finger regime. Finally we present a new result dealing with the potentially important role played by viscous dissipation in double-diffusive convection, as found in the Earth’s outer core and crust.
|Original language||English (US)|
|Title of host publication||Double-Diffusive Convection, 1995|
|Editors||Alan Brandt, H.J.S. Fernando|
|Publisher||Blackwell Publishing Ltd|
|Number of pages||15|
|State||Published - 1995|
|Name||Geophysical Monograph Series|
Bibliographical noteFunding Information:
We thank Dr. Frank J. Spera for discussions and for remarks by an anonymous reviewer. This research has been supported by the Geochemistry and the Ocean Sciences Programs of the NSF.
© 1995 by the American Geophysical Union.