Ice front shaping by upward convective current

The coupling between turbulent convecting water and the freezing/melting process leads to intriguingly complex phenomena which are of pressing importance for applications in environmental and climatological sciences. Here we study the extent and the morphology of ice forming in a differentially heated cavity filled with water by means of laboratory-scale experiments and numerical simulations. We demonstrate that the characteristic ice shape formed in our system is the result of the competition of two counterrotating convective rolls whose strength depends on the externally prescribed thermal gap.