# Multi-scale simulations of black hole accretion in barred galaxies: Numerical methods and tests

## TL;DR

This paper introduces a new numerical method for simulating gas flow in barred spiral galaxies, focusing on accurately modeling structures like nuclear rings and dust lanes using advanced computational techniques.

## Contribution

It presents a novel transport scheme for angular momentum and an efficient Poisson solver for improved simulation accuracy in galactic gas dynamics.

## Key findings

- Validated the numerical methods with tests on galactic structures
- Successfully simulated nuclear rings and dust lanes
- Enhanced accuracy in modeling gas flow in barred galaxies

## Abstract

Due to the non-axisymmetric potential of the central bar, barred spiral galaxies form, in addition to their characteristic arms and bar, a variety of structures within the thin gas disk, like nuclear rings, inner spirals and dust-lanes. In this first of two papers, we present a method to accurately simulate the gas flow within the galactic plane in the 2D finite volume software package FOSITE, which solves the transport equations for mass, momentum and energy, and apply it to this class of objects. To this extent, we introduced a new transport scheme for angular momentum and a very efficient pseudo-spectral Poisson solver. Moreover, we provide a simple and generally applicable method of how to take care of gravity in the energy equation.