Galaxies form and evolve over time in a complex, non-linear fashion. They mostly consist of a gaseous fluid that obeys hydrodynamics, but also contain many solid particles. These solid dust grains range in size from nanometers to microns and collectively absorb and scatter stellar light within galaxies. Crucially, the locations and sizes of dust grains change over time in a coupled manner through various forces and collisional processes. In this talk, I will outline methods to evolve the spatial and size distributions of dust grains during galaxy formation in a state-of-the-art astrophysics code. I will illustrate how the spatial distribution of dust is coupled to gas motion through an aerodynamic drag force. I will highlight how the methods used to evolve dust grain sizes draw on population balance equations employed in a wide variety of fields. I will demonstrate the full capability of this model using a simulation of the formation of a Milky Way-mass galaxy. In principle, the methods presented in this talk can also be used to study fluid-solid interaction in non-astrophysical settings.
