We describe new experiments in which a bubble plume, produced from a point source of bubbles, rises through an ambient fluid composed of two-layers of fluid of different density. In the lower layer, the speed of the plume exceeds the bubble rise speed and the motion is well described using classical theory of turbulent buoyant plumes.
Turbulent gravity currents are produced when a finite volume of dense fluid is rapidly released from a source above a horizontal boundary into an environment of lower density. The dense fluid propagates horizontally under gravity along the lower boundary of the flow domain by displacing the original fluid in place. Owing to the considerable importance of gravity currents in many geophysical and environmental flows, their dynamics have been studied in some detail, using a combination of laboratory experiments and mathematical models.
Focusing on simplified models of physical flow processes, this book develops a series of quantitative models to describe the recovery of oil and gas from hydrocarbon reservoirs (including fracking), the physics of geo-sequestration of CO2, geothermal power production, and the potential for underground contaminant dispersal in the long-term storage of nuclear waste. The author approaches these problems by developing simplified mathematical models and identifying the key dimensionless variables that control the processes.