论文标题
用于天体物理模拟的新的残留分布流体力学求解器
A New Residual Distribution Hydrodynamics Solver for Astrophysical Simulations
论文作者
论文摘要
只有在了解其重气体成分的行为时,才能准确地对许多天体物理系统进行建模。部分微分方程(PDE)求解器的残余分布(RD)家族对相应的流体方程产生近似溶液。我们提出了RD方法的新实现。求解器在2D和3D中有效地计算出流体的演变,在时间和空间中,在时间和空间中都有最高的二阶精度。我们实施了一种新型的变量时间步进程序,该程序采用了漂流机制来大大提高该方法的计算效率。我们对新实施进行了广泛的测试,证明了其先天的能力解决复杂的流体结构,即使是在非常低的分辨率下也是如此。我们可以通过Kelvin-Helmholtz和Sedov Blast检验来解析以3-5分辨率元件的较少分辨率元素的复杂结构。我们还注意到,我们发现冷云破坏时间尺度与典型的PPE求解器所预测的量表一致,尽管确切的进化显示出很小的差异。该代码包括三种剩余计算模式,即LDA,N和混合方案,这些方案是针对从光滑流量(LDA)到极端冲击(N)和两者(混合)的场景量身定制的。我们将RD求解器结果与其他天体物理代码中使用的最新求解器进行了比较,这表明了新方法的竞争力,尤其是在低分辨率下。这在大规模的天体物理模拟中特别感兴趣,在大规模的天体物理模拟中,重要的结构(例如恒星形成的气云)通常通过少量的流体元素来解决。
Many astrophysical systems can only be accurately modelled when the behaviour of their baryonic gas components is well understood. The residual distribution (RD) family of partial differential equation (PDE) solvers produce approximate solutions to the corresponding fluid equations. We present a new implementation of the RD method. The solver efficiently calculates the evolution of the fluid, with up to second order accuracy in both time and space, across an unstructured triangulation, in both 2D and 3D. We implement a novel variable time stepping routine, which applies a drifting mechanism to greatly improve the computational efficiency of the method. We conduct extensive testing of the new implementation, demonstrating its innate ability to resolve complex fluid structures, even at very low resolution. We can resolve complex structures with as few as 3-5 resolution elements, demonstrated by Kelvin-Helmholtz and Sedov blast tests. We also note that we find cold cloud destruction time scales consistent with those predicted by a typical PPE solver, albeit the exact evolution shows small differences. The code includes three residual calculation modes, the LDA, N and blended schemes, tailored for scenarios from smooth flows (LDA), to extreme shocks (N), and both (blended). We compare our RD solver results to state-of-the-art solvers used in other astrophysical codes, demonstrating the competitiveness of the new approach, particularly at low resolution. This is of particular interest in large scale astrophysical simulations, where important structures, such as star forming gas clouds, are often resolved by small numbers of fluid elements.