Direct numerical simulations of multiphase flow with applications to basaltic volcanism and planetary evolution

Abstract

Multiphase flows are an essential component of natural systems: They affect the explosivity of volcanic eruptions, shape the landscape of terrestrial planets, and govern subsurface flow in hydrocarbon reservoirs. Advancing our fundamental understanding and predictive capabilities of multiphase flows is a problem of immense importance for both industrial and scientific purposes. This thesis studies the potential of direct numerical simulations for advancing our fundamental understanding of the multiphase flow dynamics in magmatic flow. It is divided into two parts. The first part investigates gas-fluid coupling during the buoyant ascent of an exsolved gas phase in the conduit of basaltic volcanoes. The second part examines the solidification processes in magma oceans which entail both degassing (gas-fluid coupling) and crystallization (solid-fluid coupling). For both applications, we find that the fluid dynamics at the length scale of the interfaces has important ramifications for the large-scale behavior of the system. We conclude that direct numerical simulations are an interesting complement to more traditional computational approaches and may provide new insights into the complexity of magmatic systems.