Contour advection tracer method in smoothed particle hydrodynamics

Abstract

Studying the evolution of galaxies is important in understanding many other astrophysical phenomenon. However, this process required numerical work due to long timescales over which evolution occurs. To study the effects of chaotic mixing within a galactic disk, we implemented a contour advection method using tracers to follow the flow of gas within a disk. In this thesis, we examined effects of integration properties such as timestep normalization, artificial viscosity, temperature ceiling, and more to determine ways that our tracer method produced errors during evolution. We found that the primary issue with the tracer method was how tracers experienced shock regions, or regions of steep density contrasts. When tracers experienced too much shock heating, they overheated and were ejected from the disk, but when experiencing too little shock heating, they owed through shocks without feeling the effects. Both of these instances led to incorrect following of the gas flow.