辐射流体力学数值模拟中的隐式蒙特卡罗方法  

Implicit Monte Carlo Method in Radiation Hydrodynamics

作　　者：闫凯 YAN Kai(School of Mathematical Sciences,Peking University,Beijing 100084,China;Northwest Institute of Nuclear Technology,Xi’an 710024,China)

机构地区：[1]北京大学数学科学学院,北京100084 [2]西北核技术研究院,陕西西安710024

出　　处：《原子能科学技术》2021年第3期397-404,共8页Atomic Energy Science and Technology

摘　　要：研究了一种模拟辐射流体力学问题的隐式蒙特卡罗方法,该方法考虑了相对论效应的影响。采用算子分裂思想将问题分为3步:1)计算不含辐射与物质相互作用项的流体力学方程组;2)采用隐式蒙特卡罗方法模拟辐射输运过程,通过追踪粒子历史,采用统计的方法给出粒子在1个时间步的能量和动量沉积,在此过程中考虑了相对论效应对辐射输运的影响;3)更新流体能量和动量。在整个计算过程中,流体力学过程和蒙特卡罗粒子在介质中的运动过程均在实验室坐标系下进行模拟,但粒子的碰撞事件在局部的流体静止系下进行模拟。最后针对辐射流体力学的几个典型问题开展数值实验,计算结果验证了算法的适用性和程序的正确性。An implicit Monte Carlo method was developed to solve the radiation hydrodynamics problems,which considered the special relativistic effects.The problem was solved in three steps by using an operator-splitting manner.The first step was to calculate the hydrodynamics equation without the radiation source term.The second step was to simulate the radiation transport equation using the implicit Monte Carlo method,and the deposited energy and momentum were tallied in the particle tracking progress.The relativistic effects in this progress were considered.Lastly the momentum and energy density were updated by the statistical results of the second step.Hydrodynamics process and the motion process of Monte Carlo particle were performed in the lab frame.However,the matter-radiation interaction is in the local commoving frame.Finally,numerical experiments were carried out on several typical problems in radiation hydrodynamics.The result verifies the applicability of the method and the correctness of the code.

关 键 词：辐射流体力学 隐式蒙特卡罗方法 算子分裂 实验室坐标系 流体静止系 

分 类 号：O38[理学—流体力学] O242[理学—力学]