An open-source project for modeling hydrodynamics in astrophysical systems

Numerical modeling has proven useful in astrophysics, where many interesting problems are analytically intractable due to the presence of exotic physics and nonlinearities in the governing differential equations. Because of the unique nature of astrophysical systems, astrophysicists have developed unique numerical methods to model these problems. I describe an open-source project called Spheral++, which implements some of these numerical methods to simulate the time evolution of systems dominated by gravitation and hydrodynamics. Accurate treatment of these processes should let us examine such challenging problems as the formation and evolution of galaxies, stellar formation and collisions, and supernova. I also describe why the numerical algorithms used have evolved, how we chose to implement them in Spheral++, and the rationale for developing Spheral++ as an open-source project. I also consider why the open-source approach to software development has not prevailed in scientific software and what I think an open-source project such as this needs to succeed and be useful.