Conservative discontinuous Galerkin method for supercritical, real-fluid flows

TL;DR

This paper introduces a conservative discontinuous Galerkin method tailored for supercritical and transcritical real-fluid flows, effectively reducing pressure oscillations and ensuring stability without phase separation issues.

Contribution

It proposes an L2-projection technique within the DG framework to mitigate pressure oscillations in high-pressure real-fluid flow simulations.

Findings

The scheme converges in sinusoidal density wave advection tests.

It reduces pressure oscillations in nitrogen/n-dodecane thermal bubble simulations.

It maintains stability in complex jet injection scenarios.

Abstract

This paper presents a conservative discontinuous Galerkin method for the simulation of supercritical and transcritical real-fluid flows without phase separation. A well-known issue associated with the use of fully conservative schemes is the generation of spurious pressure oscillations at contact interfaces, which are exacerbated when a cubic equation of state and thermodynamic relations appropriate for this high-pressure flow regime are considered. To reduce these pressure oscillations, which can otherwise lead to solver divergence in the absence of additional dissipation, an L2-projection of primitive variables is performed in the evaluation of the flux. We apply the discontinuous Galerkin formulation to a variety of test cases. The first case is the advection of a sinusoidal density wave, which is used to verify the convergence of the scheme. The next two involve one- and two-dimensional advection of a nitrogen/n-dodecane thermal bubble, in which the ability of the methodology to reduce pressure oscillations and maintain solution stability is assessed. The final test cases consist of two- and three-dimensional injection of an n-dodecane jet into a nitrogen chamber.