Practical Effects of Integrating Temperature with Strang Split Reactions

TL;DR

This paper investigates the impact of integrating temperature with reaction equations in Strang splitting for astrophysical reactive flows, demonstrating improved convergence and accuracy.

Contribution

It provides evidence that including temperature in the reaction integration enhances convergence and accuracy in operator-split reactive flow simulations.

Findings

Integrating temperature yields better convergence in reactive flow models.

Second order convergence requires energy or temperature integration.

Symmetric operator splitting benefits from coupled temperature and reaction updates.

Abstract

For astrophysical reacting flows, operator splitting is commonly used to couple hydrodynamics and reactions. Each process operates independent of one another, but by staggering the updates in a symmetric fashion (via Strang splitting) second order accuracy in time can be achieved. However, approximations are often made to the reacting system, including the choice of whether or not to integrate temperature with the species. Here we demonstrate through a simple convergence test that integrating an energy equation together with reactions achieves the best convergence when modeling reactive flows with Strang splitting. Additionally, second order convergence cannot be achieved without integrating an energy or temperature equation.