不可压缩流体周期性流动格子波尔兹曼的边界处理

提出了一种新的周期性边界处理方法,用于处理格子波尔兹曼(lattice boltzmann)方法中压力驱动不可压缩流体周期性流动的边界条件。当压力驱动的不可压缩流体充分发展时,可以在周期性截面上直接用压力梯度而不是采用当量体积力的常规周期性边界处理方法,来确定周期性流动截面上的粒子分布密度。应用所提出的压力驱动不可压缩流体周期性流动的边界处理方法,对二维压力驱动下充分发展的泊肃叶流(poiseuille flow)和周期性方柱扰流进行了数值模拟。结果表明:该周期边界条件处理方法能够很好地保持系统周期性,在其宏观的周期性边界截面上产生了连续的压力分布,真正地实现了直接压力驱动不可压缩流体周期性流动条件下的所有特征。

A new boundary treatment of lattice boltzmann method (LBM) for fully developed pressure-driven periodic incompressible fluid flow

This paper proposeds a new boundary treatment of Lattice Boltzmann Method (LBM) for fully developed pressure-driven periodic incompressible fluid flow. The pressure gradient, instead of equivalent body force, is applied to determine the particle distribution function on the periodic traverse sections for the fully developed pressure-driven periodic flow. Numerical simulations, including 2D pressure-driven poiseuille flow and fluid flow passing periodic square obstacles, are carried out using this new boundary treatment. Simulation results show that the proposed approach not only overcomes the nonphysical inlet and outlet flow disturbances (which the LBM simulation always suffers from using the existing pressure boundary methods), but also preserves the system periodicity and generates consistent pressure distribution with macroscopic periodic boundary conditions for the pressure-driven incompressible fluid flow.