Abstract Previous lattice Boltzmann model (LBM) studies on solid entry/exit problems are limited to the free-surface LB model in which effects of the surface tension and gas phase are neglected, the surface wettability cannot be adjusted, boundary conditions need to be applied on the interface, and the interface has to be tracked during time. In addition, conventional macroscopic models for simulating the phenomenon such as Volume of Fluid (VOF) and Constrained Interpolation Profile (CIP) have the same difficulties with the interface, besides the higher computational cost and time. Therefore, for the first time in this paper, a robust pseudo-potential based multi-phase LB model is coupled with moving boundary LB schemes for simulating liquid entry/exit of solids with the circular cylinder as a selected case study without losing generality. The current model has none of the free-surface LBM limitations and is also superior over the conventional models by automatic interface capturing and lower computational cost and time. Furthermore, the integrated model is capable of simulating the phenomenon at relatively high We and Re numbers and density ratios as high as the water/air one. Formation and propagation of the pressure wave in the case of liquid entry are shown and discussed. Cavity and subsequent pinch-off and jets formations for a hydrophobic surface are also captured and quantified. Effects of the We, Re, Fr, and impact velocity on the pinch-off time and depth, and velocity of subsequent jets are investigated, plotted, and discussed in details. Results show that the pinch-off time and depth are independent of the surface tension and liquid viscosity, but are increased linearly with the impact velocity. Furthermore, the velocity magnitude of both downward and upward jets after the pinch-off is increased with Re and We numbers and is decreased with Fr number.

中文翻译：

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拟势格玻尔兹曼模型在模拟运动固体与液体相互作用中的应用

摘要 以往关于固体进出问题的晶格 Boltzmann 模型 (LBM) 研究仅限于自由表面 LB 模型，其中忽略了表面张力和气相的影响，无法调整表面润湿性，需要应用边界条件在接口上，并且必须在时间段内跟踪接口。此外，用于模拟流体体积 (VOF) 和约束插值剖面 (CIP) 等现象的常规宏观模型在接口方面具有相同的困难，除了更高的计算成本和时间。因此，本文第一次将基于鲁棒的赝势的多相 LB 模型与移动边界 LB 方案相结合，以在不失一般性的情况下，以圆柱体作为选定的案例研究来模拟固体的液体进出。当前模型没有自由表面 LBM 的限制，并且通过自动界面捕获和更低的计算成本和时间也优于传统模型。此外，集成模型能够模拟相对较高的 We 和 Re 数以及与水/空气一样高的密度比的现象。显示和讨论了在液体进入的情况下压力波的形成和传播。疏水表面的空腔和随后的夹断和喷射形成也被捕获和量化。We、Re、Fr 和撞击速度对夹断时间和深度的影响，以及后续射流的速度进行了详细研究、绘制和讨论。结果表明夹断时间和夹断深度与表面张力和液体粘度无关，但随着冲击速度线性增加。此外，夹断后向下和向上射流的速度大小随 Re 和 We 数增加而随 Fr 数减少。