On convective instabilities in a rotating fluid with stably stratified layer and thermally heterogeneous boundary

The onset of convection in a rotating plane layer due to vertical temperature gradient is studied this paper. background stratification modulated by lateral variations and stable aimed at understating the Earth's outer core subject thermal core–mantle interaction. At top boundary, sinusoidal Gaussian are imposed apart from reference case isothermal condition used classical Rayleigh–Benard convection. additional modulating conditions break top–bottom flow symmetry leading localization asymmetry that exhibit modified temporal dynamics unlike cells. threshold for lowered with flows occurring surplus heat flux regions caused conditions. Despite suppression layer, rapid rotation favors penetration rolls smaller wavelengths. boundary enhance such axial laterally varying penetrative extent resulting clustered structure case. With both imposed, overstable modes favored low Prandtl numbers, regime which relevant rotation, novel mode traveling wave instability occurs convection, propagation direction controlled gradients boundary. oscillatory suppressed imposition indicated significant lowering transition number.