【摘要】 本文研究熵格子Boltzmann方法(ELBM)对于高Reynolds数流动问题的适用性。ELBM由于其满足热力学第二定律,使得它比标准的格子Boltzmann方法(LBM)具有更高的数值稳定性。ELBM在计算过程中,通过调节松弛参数来确保系统符合熵日定律。在调节松弛参数时,必须求解一个非线性方程组,这使得计算量加大。本文基于Ehrenfest理论,根据简单的正性约束来保证日定律的成立。在数值实例部分,对顶盖驱动流进行了研究,给出了此方法与上述方法计算效率和正确性的一个比较,并且研究了全局熵的变化。更多还原

【Abstract】 The focus of this paper is on the applicability of entropic lattice Boltzmann method (ELBM) for high Reynolds number fluid flows.ELBM satisfies the second principle of thermody- namics,so ELBM possesses a stronger numerical stability compared with standard lattice Boltzmann method (LBM).In the process of implementing ELBM,the relaxation parameter is modified such that the population distributions of fluid systems satisfy the entropic H-theorem.When the relaxation parameter is adjusted,a nonlinear equation must be solved.So,ELBM need much more computation costs than that of the standard LBM.Based on Ehrenfest’s theory,a simple positivity-enforcing con- straint is adopted to guarantee the H-theorem.Numerical simulation of the lid-driven fluid flows is conducted to show the feasibility and efficiency of the proposed method.更多还原