论文标题
边界条件变体的分析和比较自由表面晶格boltzmann方法
Analysis and comparison of boundary condition variants in the free-surface lattice Boltzmann method
论文作者
论文摘要
自由表面晶格Boltzmann方法（FSLBM）的精度显着取决于在自由接口处使用的边界条件。理想情况下，所选边界条件平衡了液体和气压施加的力。相同边界条件的不同变体可能取决于粒子分布函数的数量和选择（PDF）。这项研究分析并比较了四个变体，其中（i）边界条件应用于所有定向的PDF，沿自由界面正常向量的相反方向，包括OR（II）排除中央PDF。尽管这些变体覆盖了现有信息，但也可以将边界条件（iii）应用于丢失的PDF，而无需丢弃可用数据或（iv）仅缺少PDF，但至少是文献中建议的至少三个PDF。结果表明，两种变体通常都平衡了自由表面液体压力和气压所施加的力。在涵盖各种应用的五个不同数值实验中，比较了四种变体的精度。这些包括站立重力波，矩形和圆柱大坝断裂，泰勒气泡的上升以及影响稀薄液体池的液滴。总体而言，在本研究中执行的数值实验中，变体（III）比其他变体要准确得多。
The accuracy of the free-surface lattice Boltzmann method (FSLBM) depends significantly on the boundary condition employed at the free interface. Ideally, the chosen boundary condition balances the forces exerted by the liquid and gas pressure. Different variants of the same boundary condition are possible, depending on the number and choice of the particle distribution functions (PDFs) to which it is applied. This study analyzes and compares four variants, in which (i) the boundary condition is applied to all PDFs oriented in the opposite direction of the free interface's normal vector, including or (ii) excluding the central PDF. While these variants overwrite existing information, the boundary condition can also be applied (iii) to only missing PDFs without dropping available data or (iv) to only missing PDFs but at least three PDFs as suggested in the literature. It is shown that neither variant generally balances the forces exerted by the liquid and gas pressure at the free surface. The four variants' accuracy was compared in five different numerical experiments covering various applications. These include a standing gravity wave, a rectangular and cylindrical dam break, a rising Taylor bubble, and a droplet impacting a thin pool of liquid. Overall, variant (iii) was substantially more accurate than the other variants in the numerical experiments performed in this study.
