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本文研究了广泛应用于耦合算法中的非周期性边界条件(NPBC),获得了耦合算法中粒子区边界附近原子所受边界力与边界处局部密度和温度的关系。基于此,本文拟合得到了边界力与局部密度和温度的关系式,与平衡态分子动力学模拟结果的对比验证了拟合公式的可靠性。最后本文将边界力的拟合公式应用到耦合算法中求解Poiseuille流动,结果表明粒子区边界附近的密度振荡大大减小,且速度和温度分布曲线能很好地与纯MD方法结果吻合。
In this paper, we study the aperiodic boundary conditions (NPBCs) which are widely used in the coupling algorithm and obtain the relationship between the boundary force and the local density and temperature at the boundary of particles in the coupled algorithm. Based on this, the relationship between the boundary force and local density and temperature is fitted and compared with the equilibrium molecular dynamics simulation results to verify the reliability of the fitting formula. Finally, the fitting formula of the boundary force is applied to the coupling algorithm to solve the Poiseuille flow. The results show that the density oscillation near the boundary of the particle area is greatly reduced, and the velocity and temperature distribution curves are in good agreement with the results of the pure MD method.