A globally hyperbolic moment system upto arbitrary order for the Wigner equation was derived in[6].For numerically solving the high order hyperbolic moment system therein,we in this paper develop a preliminary numeric...A globally hyperbolic moment system upto arbitrary order for the Wigner equation was derived in[6].For numerically solving the high order hyperbolic moment system therein,we in this paper develop a preliminary numerical method for this system following the NRxx method recently proposed in[8],to validate the moment system of the Wigner equation.The method developed can keep both mass and momentum conserved,and the variation of the total energy under control though it is not strictly conservative.We systematically study the numerical convergence of the solution to the moment system both in the size of spatial mesh and in the order of the moment expansion,and the convergence of the numerical solution of the moment system to the numerical solution of the Wigner equation using the discrete velocity method.The numerical results indicate that the high order moment system in[6]is a valid model for the Wigner equation,and the proposed numerical method for the moment system is quite promising to carry out the simulation of the Wigner equation.展开更多
We develop the dimension-reduced hyperbolic moment method for the Boltzmann equation,to improve solution efficiency using a numerical regularized moment method for problems with low-dimensional macroscopic variables a...We develop the dimension-reduced hyperbolic moment method for the Boltzmann equation,to improve solution efficiency using a numerical regularized moment method for problems with low-dimensional macroscopic variables and highdimensional microscopic variables.In the present work,we deduce the globally hyperbolic moment equations for the dimension-reduced Boltzmann equation based on the Hermite expansion and a globally hyperbolic regularization.The numbers of Maxwell boundary condition required for well-posedness are studied.The numerical scheme is then developed and an improved projection algorithm between two different Hermite expansion spaces is developed.By solving several benchmark problems,we validate the method developed and demonstrate the significant efficiency improvement by dimension-reduction.展开更多
基金supported in part by the National Basic Research Program of China(2011CB309704)Fok Ying Tong Education and NCET in China+1 种基金T.Lu was supported in part by the NSFC(11011130029,91230107)by SRF for ROCS,SEM.
文摘A globally hyperbolic moment system upto arbitrary order for the Wigner equation was derived in[6].For numerically solving the high order hyperbolic moment system therein,we in this paper develop a preliminary numerical method for this system following the NRxx method recently proposed in[8],to validate the moment system of the Wigner equation.The method developed can keep both mass and momentum conserved,and the variation of the total energy under control though it is not strictly conservative.We systematically study the numerical convergence of the solution to the moment system both in the size of spatial mesh and in the order of the moment expansion,and the convergence of the numerical solution of the moment system to the numerical solution of the Wigner equation using the discrete velocity method.The numerical results indicate that the high order moment system in[6]is a valid model for the Wigner equation,and the proposed numerical method for the moment system is quite promising to carry out the simulation of the Wigner equation.
基金supported in part by the National Basic Research Program of China(2011CB309704)the National Natural Science Foundation of China(NSFC91330205)+2 种基金supported by the Hong Kong Research Council GRF grant(PolyU 2021/12P)the Hong Kong Polytechnic University grant(A-PL61)supported by the Hong Kong RGC grant PolyU 2017/10P during their visits to the Hong Kong Polytechnic University。
文摘We develop the dimension-reduced hyperbolic moment method for the Boltzmann equation,to improve solution efficiency using a numerical regularized moment method for problems with low-dimensional macroscopic variables and highdimensional microscopic variables.In the present work,we deduce the globally hyperbolic moment equations for the dimension-reduced Boltzmann equation based on the Hermite expansion and a globally hyperbolic regularization.The numbers of Maxwell boundary condition required for well-posedness are studied.The numerical scheme is then developed and an improved projection algorithm between two different Hermite expansion spaces is developed.By solving several benchmark problems,we validate the method developed and demonstrate the significant efficiency improvement by dimension-reduction.
