Linear Stability Analysis and CFD Simulation of Double-Layer Rayleigh-Bénard Convection

Abstract

-Natural convection in superimposed layers of fluids heated from below is commonly observed in many industrial and natural situations, such as crystal growth, co-extrusion processes and atmospheric flow. The stability analysis of this system reveals a complex dynamic behavior, including the potential multiplicity of stationary states and occurrence of periodic regimes. In this study, a linear stability analysis (LSA) was performed to determine the onset of natural convection as a function of imposed boundary conditions, geometrical configuration and specific perturbations. To investigate the effects of the non-linear terms neglected in LSA, a direct simulation of the full nonlinear problem was performed using computational fluid dynamics (CFD) techniques. The numerical simulation results show an excellent agreement with the LSA results near the onset of convection and an increase in the deviation as the Rayleigh number increases above the critical value.

Simulation of Thermal Decomposition in an Open Cavity: Entropy Analysis

“…Rahman et al (2013) carried out an investigation of a two-dimensional laminar incompressible mixed convection flow in a ventilated cavity. Fontana et al (2016) carried out a comparison between linear stability analysis and numerical simulation of Rayleigh-Benard convection in double-layer channel flow. Dhiman et al (2012) analyzed the effects of blockage ratio on the cross-buoyancy around a confined square cylinder in a channel.…”