A note on reducing spurious pressure oscillations in fully conservative discontinuous Galerkin simulations of multicomponent flows

TL;DR

This paper compares strategies to reduce spurious pressure oscillations in fully conservative discontinuous Galerkin simulations of multicomponent flows, focusing on methods that preserve accuracy and conservation.

Contribution

It introduces and evaluates strategies that mitigate pressure oscillations without sacrificing conservation, artificial viscosity, or accuracy in smooth regions.

Findings

Certain strategies effectively reduce oscillations without conservation errors.

Contradictory results observed compared to hydrogen/oxygen cases.

Method performance varies with different multicomponent flow scenarios.

Abstract

A well-known issue associated with the use of fully conservative schemes in multicomponent-flow simulations is the generation of spurious pressure oscillations at contact interfaces. These oscillations can rapidly lead to solver divergence even in the presence of smooth interfaces that are not fully resolved. In this note, we compare various strategies for reducing such oscillations that do not (a) introduce conservation error, (b) rely on artificial viscosity or limiting, or (c) degrade order of accuracy in smooth regions of the flow. The considered test case is one-dimensional advection of a high-pressure nitrogen/n-dodecane thermal bubble using the thermally perfect gas model. Several results are presented that contradict those corresponding to the more conventional hydrogen/oxygen thermal-bubble case.