关于反弹格式

journeyhope

问一个很基本的问题啊
反弹格式是怎么能够保证静止壁面的速度为零的呢？
谢谢啦

luo@odu.edu

Because you can PROVE it rigorously. This can be done as the following. With simple flows (Poiseuille or Couette), you can solve the LBE with the bounce-back BCs ANALYTICALLY. Then you see why the lattice BGK model is no good and why MRT model is necessary. All these results have been published, repeatedly.

[ 本帖最后由 luo@odu.edu 于 2012-3-14 08:54 编辑 ]

phoenixchen

你初步可以这么理解：所谓的反弹就是分布函数关于壁面的反对称。在做此操作以后，密度不发生变化，但速度将反向。这和最简单的有限差分的固壁处理有点象。

hustczh

如罗老师所说，BGK模型下的反弹格式是不能保证壁面的速度为“零”的，它是松弛因子和网格数的函数，相比MRT模型则可通过调节某个松弛因子来实现壁面的速度为零，具体可以参考Ginzbourg等人的相关工作。
[1] I. Ginzbourg and P.M. Adler, Boundary condition analysis for the three-dimensional lattice Boltzmann model, J. Phys. II France, 4(1994):191

[2] X. He, et al., Analytic solutions of simple flows and analysis of nonslip boundary conditions for the lattice Boltzmann BGK model, J. Stat. Phys.,  87(1997):115

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