摘要
本文对直接力浸入边界-格子Boltzmann耦合方法中两种常用LB方程中引入外力项的方法(EBF和GZS模型)以及基于压力的He-Luo模型与基于密度的LBGK模型两种LB方程的方法分别进行了对比分析.结果表明对于不可压流动,GZS模型精度比EBF模型高,而He-Luo模型精度与比标准LBGK模型高.采用多重力法可有效减小直接力IB方法会出现的边界无滑移条件误差,发现数值边界相对物理边界产生外扩现象,通过边界内缩方法可以使得数值边界与物理边界重合,实现边界的真正无滑移条件.
Two common schemes(EBF and GZS method) introducing external force term into LB equations in direct forcing immersed boundary-lattice Boltzmann method coupling method are analyzed comparatively. Meanwhile, two common LB models are considered which one is He-Luo equation based on pressure and the other is standard LBGK equation based on density. The results show that for incompressible flow, GZS scheme and He-Luo model is more accurate than EBF scheme and LBGK model, respectively. And the error of boundary non-slip condition can be reduced effectively by multi-direct forcing strategy. Furthermore, a phenomenon that numerical boundary slightly expanded from physical boundary is intuitively found. It can be effectively corrected and hence the non-slip condition can be sufficiently satisfied by further slightly retracting the numerical boundary to coincide with the physical boundary.
引文
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