Explicit-Implicit Scheme for Relativistic Radiation Hydrodynamics
Explicit-Implicit Scheme for Relativistic Radiation Hydrodynamics
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相对论辐射流体动力学的显式-隐式方案
DOI：
10.1088/0004-637x/764/2/122
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Kengo
中科院分区：
文献类型：
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作者：
Takahashi;Hiroyuki R.; Ohsuga;Ken; Sekiguchi;Yuichiro; Inoue;Tsuyoshi; Tomida;Kengo
我们提出了一个显式-隐式格式的数值求解特殊相对论辐射流体动力学方程，它保证了总能量和动量（物质和辐射）的守恒。在本方案中，对辐射传递方程的零矩和一矩方程进行了数值求解，而不采用限制通量的扩散近似。对于一个双曲项，其时间标度是当流速与光速相当时的光穿过时间，使用近似黎曼解算器显式求解。描述物质和辐射之间通过气体-辐射相互作用的能量和动量交换的源项使用迭代方法隐式积分。隐式格式允许我们放宽光学厚介质中的Courant-Friedrichs-Lewy条件，其中加热/冷却和散射时间标度可能比动态时间标度短得多。结果表明，我们的数值代码可以通过一、二维辐射能量输运和一维辐射流体力学的测试问题。我们新开发的方案可能对许多相对论性天体物理问题有用。我们还讨论了如何将显式-隐式格式推广到相对论辐射磁流体动力学。
We propose an explicit–implicit scheme for numerically solving special relativistic radiation hydrodynamic equations, which ensures a conservation of total energy and momentum (matter and radiation). In our scheme, zeroth and first moment equations of the radiation transfer equation are numerically solved without employing a flux-limited diffusion approximation. For an hyperbolic term, of which the timescale is the light crossing time when the flow velocity is comparable to the speed of light, is explicitly solved using an approximate Riemann solver. Source terms describing an exchange of energy and momentum between the matter and the radiation via the gas–radiation interaction are implicitly integrated using an iteration method. The implicit scheme allows us to relax the Courant–Friedrichs–Lewy condition in optically thick media, where heating/cooling and scattering timescales could be much shorter than the dynamical timescale. We show that our numerical code can pass test problems of one-and two-dimensional radiation energy transport, and one-dimensional radiation hydrodynamics. Our newly developed scheme could be useful for a number of relativistic astrophysical problems. We also discuss how to extend our explicit–implicit scheme to the relativistic radiation magnetohydrodynamics.