TY - JOUR T1 - Weakly nonlinear analysis of Rayleigh–Bénard convection problem in extended Boussinesq approximation A1 - Dostalík, Mark A1 - Matyska, Ctirad A1 - Průša, Vít JA - Applied Mathematics and Computation Y1 - 2021 VL - 408 SP - 126374 SN - 0096-3003 UR - https://www.sciencedirect.com/science/article/pii/S009630032100463X M2 - doi: 10.1016/j.amc.2021.126374 KW - Extended boussinesq approximation KW - Thermal convection KW - Weakly nonlinear analysis N2 - We investigate Rayleigh–Bénard convection problem in an extended Boussinesq approximation suitable for conditions in the Earths mantle. The aim is to evaluate the influence of depth-dependent material parameters, dissipation, adiabatic heating/cooling and heat sources on qualitative characteristics of thermal convection. We identify the critical values of dimensionless parameters that determine the onset of convection, and we characterize the dominating convection patterns in marginally supercritical states. These issues are addressed by the application of linear stability analysis and weakly nonlinear analysis. We have found that the character of convection differs substantially from the standard case of Rayleigh–Bénard convection. ER -