Mechanics of Methane Bubbles in Tailings Ponds

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This project will study how bubbles are nucleated and grow within the different layers of a tailings pond. The sludge-like material formed below the water layer has a material property called a yield stress (similar to e.g. hair gel or yoghurt) that allows the liquid to remain stiff where more conventional liquids (e.g. water) would flow. This same property also allows for bubbles to be trapped within the liquid. This project asks the question of whether bubbles move or remain static, e.g. how big must bubbles become to move, how many small bubbles can we trap in the sludge, how stable would the bubble-laden layers be? Moving bubbles (methane) are released to the atmosphere as greenhouse gases, so we would like to estimate and possibly control that mechanism. We are also interested to estimate whether a catastrophic failure could occur, where all the pond layers destabilize and release their bubbles as a form of eruption. This project will involve a mix of computational modelling, lab experiments and mathematical analysis. The experiments are designed to allow direct visualization of bubble growth/motion. Both these and the models will allow us to experiment with different ways of controlling the underlying processes that allow gas release, e.g. preventing production, limiting growth, limiting motion. As well as covering questions of practical interest for the oil sands industry, these are challenging and interesting areas for fluid mechanics.