论文标题

熵稳定的自适应移动网格方案,用于2D和3D特殊相对论水动力学

Entropy stable adaptive moving mesh schemes for 2D and 3D special relativistic hydrodynamics

论文作者

Duan, Junming, Tang, Huazhong

论文摘要

本文为2D和3D特殊相对论水动力学(RHD)方程提供了熵稳定(ES)自适应移动网格方案。它们建立在曲线坐标,离散的几何保护法中RHD方程的ES有限体积近似以及通过迭代求解网状适应性函数的Euler-Lagrange方程在计算域中具有适当选择的监视器功能的效果。首先,通过模仿曲线坐标中连续的熵身份的推导,并使用保守的度量方法给出的离散几何保护法,证明了两点熵保守(EC)通量的足够条件。基于这种足够的条件,得出了曲线坐标中RHD方程的EC通量,并开发了二阶准确的半凝结EC方案,以满足给定凸熵对的熵身份。接下来,通过向EC方案添加合适的耗散项并利用缩放熵变量中的MinMod限制器使用线性重构来抑制上述EC方案的数值振荡,提出了满足熵不等式的半分化ES方案。然后,通过使用二阶强稳定性保留显式runge-kutta方案,将半分化的ES方案在时间上集成。最后,几个数值结果表明,我们的2D和3D ES自适应移动网格方案有效地捕获了局部结构,例如锐利的过渡或不连续性,并且比在均匀网格上的对应物更有效。

This paper develops entropy stable (ES) adaptive moving mesh schemes for the 2D and 3D special relativistic hydrodynamic (RHD) equations. They are built on the ES finite volume approximation of the RHD equations in curvilinear coordinates, the discrete geometric conservation laws, and the mesh adaptation implemented by iteratively solving the Euler-Lagrange equations of the mesh adaption functional in the computational domain with suitably chosen monitor functions. First, a sufficient condition is proved for the two-point entropy conservative (EC) flux, by mimicking the derivation of the continuous entropy identity in curvilinear coordinates and using the discrete geometric conservation laws given by the conservative metrics method. Based on such sufficient condition, the EC fluxes for the RHD equations in curvilinear coordinates are derived and the second-order accurate semi-discrete EC schemes are developed to satisfy the entropy identity for the given convex entropy pair. Next, the semi-discrete ES schemes satisfying the entropy inequality are proposed by adding a suitable dissipation term to the EC scheme and utilizing linear reconstruction with the minmod limiter in the scaled entropy variables in order to suppress the numerical oscillations of the above EC scheme. Then, the semi-discrete ES schemes are integrated in time by using the second-order strong stability preserving explicit Runge-Kutta schemes. Finally, several numerical results show that our 2D and 3D ES adaptive moving mesh schemes effectively capture the localized structures, such as sharp transitions or discontinuities, and are more efficient than their counterparts on uniform mesh.

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