This video shows the result of a set of stochastic model simulations of free convection. Each column represents one of four hydraulic conductivity realizations, which are shown along the top row. The second row shows the results for the homogeneous case, whereas the standard deviation of the log k field increases in each of the consecutive rows going downward. Many things can be seen in this video but two things are key: The first is that fingering occurs fastest in simulations where the standard deviation is highest, so heterogeneity promotes free convection. The second is that low-permeability structures (which show up dark blue in the figures in the top row) obstruct downward sinking plumes, meaning that heterogeneity can also stabilize convective flow systems. (1 minute)
A discussion of the material in this video is provided in Section 6.3 ‘Predictability of Convective Flow Patterns’ of the Groundwater Project book ‘Variable Density Groundwater Flow’, the PDF can be downloaded or the online version can be read at that link.
Citation: Post, V.E.A. & Simmons, C.T. (2022). Variable Density: Simulations of free convection in a set of four stochastic model simulations with varying degrees of heterogeneity. Video of The Groundwater Project, Guelph, Ontario, Canada.