Shear flows and their suppression at large aspect ratio: Two-dimensional simulations of a growing convection zone

Shear flows can form spontaneously in two-dimensional (2D) simulations of convection. These disperse convective plumes and decrease vertical transport. What is the physics these flows? Can they be avoided 2D? It was previously shown that increasing simulation aspect ratio prevent onset shear flows. With penetrative convection we explore a range ratios. We find small perturbations lead to formation strong by taking energy from motions, but are suppressed domains large ratio. This could allow 2D studies at lower computational cost than 3D simulations.