## Gravity currents: entrainment, stratification and self-similarity

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.