In this paper,Runge-Kutta Discontinuous Galerkin（RKDG） finite element method is presented to solve the onedimensional inviscid compressible gas dynamic equations in a Lagrangian coordinate.The equations are discreti...In this paper,Runge-Kutta Discontinuous Galerkin（RKDG） finite element method is presented to solve the onedimensional inviscid compressible gas dynamic equations in a Lagrangian coordinate.The equations are discretized by the DG method in space and the temporal discretization is accomplished by the total variation diminishing Runge-Kutta method.A limiter based on the characteristic field decomposition is applied to maintain stability and non-oscillatory property of the RKDG method.For multi-medium fluid simulation,the two cells adjacent to the interface are treated differently from other cells.At first,a linear Riemann solver is applied to calculate the numerical ？ux at the interface.Numerical examples show that there is some oscillation in the vicinity of the interface.Then a nonlinear Riemann solver based on the characteristic formulation of the equation and the discontinuity relations is adopted to calculate the numerical ？ux at the interface,which suppresses the oscillation successfully.Several single-medium and multi-medium fluid examples are given to demonstrate the reliability and efficiency of the algorithm.展开更多
达到或者超过100 k W的激光输出是激光武器用于反导反卫等战略防御的终极发展目标。基于激光武器发展目标与最新动向,提出了多模式激光复合损伤新思路,即采用不同波长、连续与脉冲、频率变化的激光,同时或交替作用在同一靶材上,获得更...达到或者超过100 k W的激光输出是激光武器用于反导反卫等战略防御的终极发展目标。基于激光武器发展目标与最新动向,提出了多模式激光复合损伤新思路,即采用不同波长、连续与脉冲、频率变化的激光,同时或交替作用在同一靶材上,获得更好的损伤效果。构建了脉冲/连续激光复合损伤物理模型,并用有限元法进行了仿真模拟,使用2 k W连续激光器与10 J长脉冲激光器开展了损伤对比实验。模拟和实验结果表明,脉冲激光烧蚀金属靶材效果优于连续激光;在两种激光复合或交替作用下出现"非线性雪崩烧蚀"效应,复合烧蚀效果明显优于脉冲激光,烧蚀质量是脉冲激光的13倍。这一效应,为战术激光武器向"合束多模式同轴输出"新体制发展提供了基础。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11261035,11171038,and 10771019)the Science Reaearch Foundation of Institute of Higher Education of Inner Mongolia Autonomous Region,China (Grant No. NJZZ12198)the Natural Science Foundation of Inner Mongolia Autonomous Region,China (Grant No. 2012MS0102)
文摘In this paper,Runge-Kutta Discontinuous Galerkin（RKDG） finite element method is presented to solve the onedimensional inviscid compressible gas dynamic equations in a Lagrangian coordinate.The equations are discretized by the DG method in space and the temporal discretization is accomplished by the total variation diminishing Runge-Kutta method.A limiter based on the characteristic field decomposition is applied to maintain stability and non-oscillatory property of the RKDG method.For multi-medium fluid simulation,the two cells adjacent to the interface are treated differently from other cells.At first,a linear Riemann solver is applied to calculate the numerical ？ux at the interface.Numerical examples show that there is some oscillation in the vicinity of the interface.Then a nonlinear Riemann solver based on the characteristic formulation of the equation and the discontinuity relations is adopted to calculate the numerical ？ux at the interface,which suppresses the oscillation successfully.Several single-medium and multi-medium fluid examples are given to demonstrate the reliability and efficiency of the algorithm.
文摘达到或者超过100 k W的激光输出是激光武器用于反导反卫等战略防御的终极发展目标。基于激光武器发展目标与最新动向,提出了多模式激光复合损伤新思路,即采用不同波长、连续与脉冲、频率变化的激光,同时或交替作用在同一靶材上,获得更好的损伤效果。构建了脉冲/连续激光复合损伤物理模型,并用有限元法进行了仿真模拟,使用2 k W连续激光器与10 J长脉冲激光器开展了损伤对比实验。模拟和实验结果表明,脉冲激光烧蚀金属靶材效果优于连续激光;在两种激光复合或交替作用下出现"非线性雪崩烧蚀"效应,复合烧蚀效果明显优于脉冲激光,烧蚀质量是脉冲激光的13倍。这一效应,为战术激光武器向"合束多模式同轴输出"新体制发展提供了基础。
