Computer simulation of liquids
Computer simulation of liquids
Scalar and parallel optimized implementation of the direct simulation Monte Carlo method
Journal of Computational Physics
v-DSMV: a fast simulation method for rarefield flow
Journal of Computational Physics
Molecular Dynamics Simulation: Elementary Methods
Molecular Dynamics Simulation: Elementary Methods
Understanding Molecular Simulation
Understanding Molecular Simulation
Event-driven molecular dynamics in parallel
Journal of Computational Physics
Journal of Computational Physics
A Complexity O(1) priority queue for event driven molecular dynamics simulations
Journal of Computational Physics
Higher moments of the velocity distribution function in dense-gas shocks
Journal of Computational Physics
Hi-index | 31.45 |
A novel combined Event-Driven/Time-Driven (ED/TD) algorithm to speed-up the Molecular Dynamics simulation of rarefied gases using realistic spherically symmetric soft potentials is presented. Due to the low density regime, the proposed method correctly identifies the time that must elapse before the next interaction occurs, similarly to Event-Driven Molecular Dynamics. However, each interaction is treated using Time-Driven Molecular Dynamics, thereby integrating Newton's Second Law using the sufficiently small time step needed to correctly resolve the atomic motion. Although infrequent, many-body interactions are also accounted for with a small approximation. The combined ED/TD method is shown to correctly reproduce translational relaxation in argon, described using the Lennard-Jones potential. For densities between @r=10^-^4kg/m^3 and @r=10^-^1kg/m^3, comparisons with kinetic theory, Direct Simulation Monte Carlo, and pure Time-Driven Molecular Dynamics demonstrate that the ED/TD algorithm correctly reproduces the proper collision rates and the evolution toward thermal equilibrium. Finally, the combined ED/TD algorithm is applied to the simulation of a Mach 9 shock wave in rarefied argon. Density and temperature profiles as well as molecular velocity distributions accurately match DSMC results, and the shock thickness is within the experimental uncertainty. For the problems considered, the ED/TD algorithm ranged from several hundred to several thousand times faster than conventional Time-Driven MD. Moreover, the force calculation to integrate the molecular trajectories is found to contribute a negligible amount to the overall ED/TD simulation time. Therefore, this method could pave the way for the application of much more refined and expensive interatomic potentials, either classical or first-principles, to Molecular Dynamics simulations of shock waves in rarefied gases, involving vibrational nonequilibrium and chemical reactivity.