Many astrophysical environments involve convective or explosive flows driven by thermonuclear reactions (Type Ia supernovae, classical novae, X-ray bursts, stellar evolution). Simulation codes need to accurately capture the interactions between reactions and hydrodynamics to produce realistic models of these events. 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.

许多天体物理环境涉及由热核反应（Ia 型超新星、经典新星、X 射线爆发、恒星演化）驱动的对流或爆炸流动。模拟代码需要准确捕捉反应和流体动力学之间的相互作用，以生成这些事件的真实模型。对于天体物理反应流，算子分裂通常用于耦合流体动力学和反应。每个过程彼此独立运行，但通过以对称方式（通过 Strang 分裂）交错更新可以实现时间上的二阶精度。然而，通常对反应系统进行近似，包括选择是否将温度与物质结合。在这里，我们通过一个简单的收敛测试证明，在使用 Strang 分裂对反应流进行建模时，将能量方程与反应相结合可以实现最佳收敛。此外，如果不积分能量或温度方程，就无法实现二阶收敛。