Grain Dynamics in Astrophysical Simulations

Ryan McKinnon, Massachusetts Institute of Technology

The dynamics of solid-grain particles in a fluid medium are relevant in many scientific fields. In astrophysics, solid dust grains absorb and reradiate stellar light, affecting the spectroscopic properties of galaxies. This work focuses on modeling the hydrodynamical drag force that couples grain and fluid motions. I implement this drag force in the moving-mesh hydrodynamics code AREPO and validate it using a variety of hydrodynamical test problems, including a Sod shock tube and a Sedov-Taylor blast wave. The convergence properties of drag integrators, both explicit and semi-implicit, are discussed. I also outline how grain dynamics can be coupled to other topics important in astrophysics, including magnetohydrodynamics and radiative transfer.

Abstract Author(s): Ryan McKinnon, Mark Vogelsberger, Paul Torrey, Federico Marinacci, Rahul Kannan