基于边界增厚的直接强迫浸没边界法全分辨模拟含颗粒流动
A Boundary Thickening-based Direct Forcing Immersed Boundary Method for Fully Resolved Simulation of Particle-laden Flows
摘要：
提出了一种基于边界增厚的直接强迫（BTDF）浸没边界（IB）方法，用于有限尺寸颗粒不可压粘性流动的全分辨模拟。通过稍微加厚边界厚度，固体边界上的拉格朗日点与其相邻的流体欧拉网格之间的局部通信得到改善，基于隐式直接强迫（IDF）方法和正则化δ函数的单位分割条件。这种策略产生了一个简单的，但更好地施加无滑移和无渗透的边界条件比传统的直接强迫（DF）技术。特别是，该BTDF方法可以达到与其他代表性的改进方法，如多直接强迫（multi-direct forcing，简称DF）、隐式速度校正（implicit velocity correction，简称IVC）和再生核粒子方法（reproducing kernel particle method，简称RKPM）相媲美的数值精度，而其计算成本却保持得很低，与传统DF方法几乎相当。还揭示了边界增厚的最佳厚度值对正则化δ函数形式的依赖性。通过将格子玻尔兹曼方法（LBM）与BTDF-IB耦合，对圆柱绕流的爬行流动（Re=0.1）、定常旋涡分离流动（Re=40）和非定常旋涡脱落流动（Re=200）进行了数值模拟，验证了BTDF-IB方法的鲁棒性。
英文摘要：
A boundary thickening-based direct forcing (BTDF) immersed boundary (IB) method is proposed for fully resolved simulation of incompressible viscous flows laden with finite size particles. By slightly thickening the boundary thickness, the local communication between the Lagrangian points on the solid boundary and their neighboring fluid Eulerian grids is improved, based on an implicit direct forcing (IDF) approach and a partition-of-unity condition for the regularized delta function. This strategy yields a simple, yet much better imposition of the no-slip and no-penetration boundary conditions than the conventional direct forcing (DF) technique. In particular, the present BTDF method can achieve a numerical accuracy comparable with other representative improved methods, such as multi-direct forcing (MDF), implicit velocity correction (IVC) and the reproducing kernel particle method (RKPM), while its computation cost remains much lower and nearly equivalent to the conventional DF scheme. The dependence of the optimum thickness value of boundary thickening on the form of the regularized delta functions is also revealed. By coupling the lattice Boltzmann method (LBM) with BTDF-IB, the robustness of the present BTDF IB method is demonstrated using numerical simulations of creeping flow (Re=0.1), steady vortex separating flow (Re=40) and unsteady vortex shedding flow (Re=200) around a circular cylinder.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
