Natural convection in air-filled differentially heated isoflux cavities: Scalings and transition to unsteadiness, a long story made short

We investigate numerically the transition to unsteadiness of natural convection in air filled differentially heated cavities and cooled with uniform flux at their vertical boundaries. This is done using both time integration nonlinear equations linearized around a steady solution computation leading eigenvalues Jacobian solutions. Results are given for values aspect ratio ranging from 0.2 8. In square cavity occurs value Rayleigh number very close 4.5×1012. characterize different groups eigenmodes Jacobian. show that modes responsible characterized by wavelike structure constant wavelength whose amplitude increases exponentially height upward boundary layer along wall. that, criticality, wave characteristics fair agreement linear stability analysis buoyancy layer. also discuss evolution layout ratio.