Dynamics in a stellar convective layer and at its boundary: Comparison of five 3D hydrodynamics codes
Dynamics in a stellar convective layer and at its boundary: Comparison of five 3D hydrodynamics codes
复制标题
恒星对流层及其边界的动力学：五个 3D 流体动力学代码的比较
DOI：
10.1051/0004-6361/202142557
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发表时间：
2022
影响因子：
6.5
通讯作者：
Edelmann, P. V.
中科院分区：
文献类型：
--
作者：
Andrassy, R.;Higl, J.;Mao, H.;Mocák, M.;Vlaykov, D. G.;Arnett, W. D.;Baraffe, I.;Campbell, S. W.;Constantino, T.;Edelmann, P. V.
我们预测恒星结构和演化的能力在一定程度上受到复杂的三维流体动力学过程（如对流边界混合）的限制。流体动力学模拟有助于我们理解恒星对流和对流边界的动力学。然而，用于计算这种模拟的代码通常在非常简单的问题上进行测试，并且其湍流预测的可靠性和可重复性尚不清楚。我们定义了一个测试问题，涉及湍流对流在一个平面平行的盒子，这将导致质量夹带，内波生成，稳定分层层。我们比较了FLASH，MUSIC，PPMSTAR，PROMPI和SLH程序的输出，这些程序已被广泛用于研究恒星内部的流体动力学问题。对流由适合模拟框的最大尺度控制。在给定的网格（1283和2563网格单元）上，所有的速度分量、脉动幅度、焓通量和动能通量的时间平均剖面都在所有模拟平均值的± 3σ之内，其中σ描述了由于流动的时间依赖性而引起的统计变化。它们也与5123参考运行一致。1283和2563的模拟结果分别在9%和4%的范围内吻合。在我们的装置中，卷吸率似乎是由可以转换为功的能量的大小决定的，而边界层中小尺度流动的细节似乎在很大程度上是无关紧要的。我们的研究结果为恒星内部流动的流体动力学模拟提供了依据。我们以电子形式提供模拟的所有输出以及复制或扩展研究所需的所有信息。
Our ability to predict the structure and evolution of stars is in part limited by complex, 3D hydrodynamic processes such as convective boundary mixing. Hydrodynamic simulations help us understand the dynamics of stellar convection and convective boundaries. However, the codes used to compute such simulations are usually tested on extremely simple problems and the reliability and reproducibility of their predictions for turbulent flows is unclear. We define a test problem involving turbulent convection in a plane-parallel box, which leads to mass entrainment from, and internal-wave generation in, a stably stratified layer. We compare the outputs from the codes FLASH, MUSIC, PPMSTAR, PROMPI, and SLH, which have been widely employed to study hydrodynamic problems in stellar interiors. The convection is dominated by the largest scales that fit into the simulation box. All time-averaged profiles of velocity components, fluctuation amplitudes, and fluxes of enthalpy and kinetic energy are within ≲3σof the mean of all simulations on a given grid (1283and 2563grid cells), whereσdescribes the statistical variation due to the flow’s time dependence. They also agree well with a 5123reference run. The 1283and 2563simulations agree within 9% and 4%, respectively, on the total mass entrained into the convective layer. The entrainment rate appears to be set by the amount of energy that can be converted to work in our setup and details of the small-scale flows in the boundary layer seem to be largely irrelevant. Our results lend credence to hydrodynamic simulations of flows in stellar interiors. We provide in electronic form all outputs of our simulations as well as all information needed to reproduce or extend our study.