论文标题
用于多尺度粒子动力学模拟的指数BGK积分器
Exponential BGK Integrator for Multi-Scale Particle-Based Kinetic Simulations
论文作者
论文摘要
尽管开发了多尺度稀有流量模拟器的广泛工具箱，但由于碰撞和宏观时空尺度的显着差异，此类模拟仍然具有挑战性。我们的研究提供了一种新颖且一致的数值方案，用于对BGK进化控制的颗粒对流和碰撞的耦合处理，从而尊重速度分布的阳性。我们的方法与统一的多尺度方案的统一气体动力学类别共享其框架。然而，它为基于粒子的随机仿真提供了吸引人的功能，可容易实现到现有的直接模拟蒙特卡洛代码。我们在广泛的稀疏参数上证明了原型气流设计方案的准确性和性能。由于设计的指数BGK积分器的稳健性和灵活性，该方案为更负担得起的大型和多尺度稀有气体现象的模拟铺平了道路。
Despite the development of an extensive toolbox of multi-scale rarefied flow simulators, such simulations remain challenging due to the significant disparity of collisional and macroscopic spatio-temporal scales. Our study offers a novel and consistent numerical scheme for a coupled treatment of particles advection and collision governed by the BGK evolution, honouring positivity of the velocity distribution. Our method shares its framework, in spirit, with the unified gas kinetic class of multi-scale schemes. Yet it provides attractive features for particle-based stochastic simulations, readily implementable to existing direct simulation Monte-Carlo codes. We demonstrate accuracy and performance of the devised scheme for prototypic gas flows, over a wide-range of rarefaction parameters. Due to the resulting robustness and flexibility of the devised exponential BGK integrator, the scheme paves the way towards more affordable simulations of large- and multi-scale rarefied gas phenomena.
