Investigation of lock-exchange turbidity currents using time-resolved X-ray densitometry

Turbidity currents form when a dense mixture of sediment and fluid moves into lighter ambient fluid due to density differences and gravity. Understanding the mechanisms of the onset, development, and propagation of such solid-liquid flows using experiments remains challenging due to the optical opacity of such flows. In this study, the mechanisms of formation and evolution of lock-exchange turbidity currents are sought by using time-resolved X-ray densitometry. The line-of-sight averaged measurements are performed for a range of particle sizes, densities, water depths, in both Bousinesq and non-Bousinesq limits. By qualitative and quantitative analysis of the measured sand volume fraction fields, the development, acceleration, and slumping phases of currents with different sand sizes and column heights are presented. The entrainment and evolution of the current head density profile are discussed from the time-resolved X-ray-based density field measurements.