[U-02_28AM1] Particle Geophysics

★ [U02-03] Development of coupled Stokes--DEM simulation scheme for geodynamical magmatic studies

*Mikito FURUICHI¹, Daisuke NISHIURA¹ (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:Magma, Particle-Laden flow, Stokes flow, Discrete element method, Melt roof, Numerical simulation

For geodynamical magmatic studies such as crystal settling at the melting roof of a magma chamber, we develop a robust and efficient simulation scheme for solving high-viscosity fluid and particle dynamics in a coupled computational fluid dynamics and discrete element method (CFD--DEM) framework. The high-viscosity fluid is treated by the Stokes-flow approximation, where the fluid interacts with particles via the drag force in a cell-averaged manner. The particles are tracked with contact forces by DEM. To efficiently solve such Stokes--DEM coupled equations, we propose two key techniques. One is formulation of particle motion without the inertial term, allowing a larger time step at higher viscosities. The other is a semi-implicit treatment of the cell-averaged particle velocity in the fluid equation to stabilize the calculation. We will explain some details of our model developments in the presentation. A series of numerical experiments shows that our proposed scheme can handle sinking particles in a high-viscosity fluid; such problems are difficult for the conventional CFD--DEM method. Then we will discuss our targeting geodynamical problems tackled with this simulation method.