# A high-order nonconservative approach for hyperbolic equations in fluid dynamics

## TL;DR

This paper introduces a high-order nonconservative numerical approach for hyperbolic fluid dynamics equations, enabling oscillation-free solutions and effective handling of nonlinear equations of state, with extensions to multiphase and multidimensional flows.

## Contribution

It demonstrates how to obtain relevant weak solutions using a pressure-based formulation, addressing long-standing issues with nonconservative schemes in fluid dynamics.

## Key findings

- Relevance of pressure-based formulation for weak solutions
- Oscillation-free solutions in nonconservative schemes
- Extensions to multiphase and multidimensional flows

## Abstract

It is well known, thanks to Lax-Wendroff theorem, that the local conservation of a numerical scheme for a conservative hyperbolic system is a simple and systematic way to guarantee that, if stable, a scheme will provide a sequence of solutions that will converge to a weak solution of the continuous problem. In [1], it is shown that a nonconservative scheme will not provide a good solution. The question of using, nevertheless, a nonconservative formulation of the system and getting the correct solution has been a long-standing debate. In this paper, we show how get a relevant weak solution from a pressure-based formulation of the Euler equations of fluid mechanics. This is useful when dealing with nonlinear equations of state because it is easier to compute the internal energy from the pressure than the opposite. This makes it possible to get oscillation free solutions, contrarily to classical conservative methods. An extension to multiphase flows is also discussed, as well as a multidimensional extension.