TY - JOUR
T1 - Shear and mixing in oscillatory doubly diffusive convection
AU - Paparella, Francesco
AU - Spiegel, Edward A.
AU - Talon, Suzanne
N1 - Funding Information:
We thank the GFD program for bringing us all together. E.A. Spiegel was supported by NSF Applied Mathematics under DMS-99-72022. S. Talon was supported by NSERC of Canada and by the Canada Research Chair in Stellar Astrophysics awarded to Gilles Fontaine. We are grateful to Barry Ruddick for his comments which contributed to improve this manuscript and to Bill Young who helped us clarifying the issue of what defines mixing.
PY - 2002/8
Y1 - 2002/8
N2 - To investigate the mechanism of mixing in oscillatory doubly diffusive (ODD) convection, we truncate the horizontal modal expansion of the Boussinesq equations to obtain a simplified model of the process. In the astrophysically interesting case with low Prandtl number (traditionally called semiconvection), large-scale shears are generated as in ordinary thermal convection. The interplay between the shear and the oscillatory convection produces intermittent overturning of the fluid with significant mixing. By contrast, in the parameter regime appropriate to sea water, large-scale flows are not generated by the convection. However, if such flows are imposed externally, intermittent overturning with enhanced mixing is observed.
AB - To investigate the mechanism of mixing in oscillatory doubly diffusive (ODD) convection, we truncate the horizontal modal expansion of the Boussinesq equations to obtain a simplified model of the process. In the astrophysically interesting case with low Prandtl number (traditionally called semiconvection), large-scale shears are generated as in ordinary thermal convection. The interplay between the shear and the oscillatory convection produces intermittent overturning of the fluid with significant mixing. By contrast, in the parameter regime appropriate to sea water, large-scale flows are not generated by the convection. However, if such flows are imposed externally, intermittent overturning with enhanced mixing is observed.
KW - Mixing
KW - Oscillatory doubly diffusive convection
KW - Semiconvection
KW - Shear
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U2 - 10.1080/03091920290029031
DO - 10.1080/03091920290029031
M3 - Article
AN - SCOPUS:33646061844
SN - 0309-1929
VL - 96
SP - 271
EP - 289
JO - Geophysical and Astrophysical Fluid Dynamics
JF - Geophysical and Astrophysical Fluid Dynamics
IS - 4
ER -