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arXiv 2007.12884math.NAcs.NA
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二维和三维狭义相对论流体力学的熵稳定自适应动网格格式

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

Junming Duan, Huazhong Tang

摘要:

针对二维和三维狭义相对论流体动力学方程,发展了熵稳定的自适应动网格格式。它们建立在曲线坐标中RHD方程的ES有限体积近似、离散几何守恒律和通过迭代求解网格自适应泛函的欧拉-拉格朗日方程来实现的网格自适应上,其中网格自适应泛函在计算域中具有适当选择的监控函数。首先,通过模仿曲线坐标中连续熵恒等式的推导,利用守恒度量方法给出的离散几何守恒律,证明了两点熵守恒通量的一个充分条件.在此充分条件下,导出了曲线坐标下RHD方程的EC通量,并构造了二阶精度的半离散EC格式,以满足给定凸熵对的熵恒等式.其次,通过在EC格式中加入适当的耗散项,并在标度熵变量中采用minmod限制器进行线性重构,得到满足熵不等式的半离散ES格式,以抑制EC格式的数值振荡.然后,半离散ES格式的时间积分使用二阶强稳定性保持显式Runge-Kutta格式。最后,一些数值结果表明,我们的2D和3D ES自适应移动网格计划有效地捕捉局部结构,如尖锐的过渡或不连续性,并比均匀网格上的同行更有效。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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