2011/04/20 by Radostin D. Simitev, R. D. Simitev · 12 citations
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Annulus (botany) #Buoyancy #Combined forced and natural convection #Convection #Convection cell #Convective instability #Double diffusive convection #Geology and Paleoclimatology Research #Geomagnetism and Paleomagnetism Studies #Materials science #Mechanics #Natural convection #Physics #Rayleigh number #Rayleigh–Bénard convection #Solar and Space Plasma Dynamics #Thermal #Thermodynamics #physics.flu-dyn #physics.geo-ph
paper · pdf · doi:10.1016/j.pepi.2011.04.007
published in Physics of The Earth and Planetary Interiors 186(3-4), 183-190 (Elsevier BV) · Accepted for publication in Physics of the Earth and Planetary Interiors on 20 April 2011
arxiv created 2011/04/20 · arxiv updated 2011/04/26 · openalex publication_date 2011/04/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Double-diffusive convection driven by both thermal and compositional buoyancy in a rotating cylindrical annulus with conical caps is considered with the aim to establish whether a small fraction of compositional buoyancy added to the thermal buoyancy (or vice versa) can significantly reduce the critical Rayleigh number and amplify convection in planetary cores. It is shown that the neutral surface describing the onset of convection in the double-buoyancy case is essentially different from that of the well-studied purely thermal case, and does indeed allow the possibility of low-Rayleigh number convection. In particular, isolated islands of instability are formed by an additional "double-diffusive" eigenmode in certain regions of the parameter space. However, the amplitude of such low-Rayleigh number convection is relatively weak. At similar flow amplitudes purely compositional and double-diffusive cases are characterized by a stronger time dependence compared to purely thermal cases, and by a prograde mean zonal flow near the inner cylindrical surface. Implications of the results for planetary core convection are briefly discussed.