ULULA: An ultra-lightweight 2D hydrodynamics code for teaching and experimentation

TL;DR

ULULA is a simple, open-source 2D hydrodynamics code designed for teaching and experimentation, emphasizing ease of understanding and extension with minimal code complexity.

Contribution

The paper introduces ULULA, a lightweight Python hydrodynamics code that simplifies complex software for educational purposes and easy experimentation.

Findings

Runs well on laptops for common problems

Includes a robust MUSCL-Hancock scheme with customizable components

Contains numerous well-known hydrodynamics problems

Abstract

Hydrodynamics is a difficult subject to teach in the classroom because most relevant problems must be solved numerically rather than analytically. While there are numerous public hydrodynamics codes, the complexity of production-level software obscures the underlying physics and can be overwhelming to first-time users. Here we present ULULA, an ultra-lightweight python code to solve hydrodynamics and gravity in 2D. The main goal is for the code to be easy to understand, extend, and experiment with. The simulation framework consists of fewer than 800 active lines of pure python code, but it includes a robust MUSCL-Hancock scheme with exchangeable components such as Riemann solvers, reconstruction schemes, boundary conditions, and equations of state. Numerous well-known hydrodynamics problems are provided and can be run in a few minutes on a laptop. The code is open-source, generously commented, and extensively documented.