Transitional multiphase flow: the enigmatic behaviour of seafloor landslides

Underwater landslides generate some of the largest and most dangerous sedimentary flows in the world. These flows may cause catastrophic damage to infrastructure in their path such as telecommunications cables (which carry 95% of international traffic) and petroleum installations (Chevron recently invested ~$3,000,000,000 to protect one 140km-long stretch of pipeline). For a typical landslide a series of transitions is inferred to occur between, pre-failure seafloor material, high concentration viscoplastic flow and the ultimate low concentration turbulent flow. However, the evolution of the processes underpinning flow evolution remain poorly understood, and consequently, the length- and time scales over which the flow transitions occur remain the subject of intense debate, not only with respect to constraining geohazard risk, but also because of the implications for understanding and predicting the character of any resulting sedimentary deposits. The study will initially focus on the dynamics of failure and flow of non-cohesive slope material; a secondary goal will be to model cohesive effects. This research has application to flow runout prediction (geohazard risk) and deposit characterization (petroleum reservoir appraisal) and will be based on the development of simplified shallow-layer continuum models, open source smoothed-particle-hydrodynamic models and idealized experiments.