Lattice Boltzmann simulation of rising bubble dynamics using an effective buoyancy method
Lattice Boltzmann simulation of rising bubble dynamics using an effective buoyancy method
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DOI：
10.1142/s012918311550031x
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发表时间：
2015-02
影响因子：
1.9
通讯作者：
M. Ngachin;R. Galdamez;S. Gokaltun;M. Sukop
中科院分区：
文献类型：
--
作者：
M. Ngachin;R. Galdamez;S. Gokaltun;M. Sukop
本文利用Shan和chen型多组分多相晶格玻尔兹曼方法（LBM）描述了气泡在重力作用下上升的行为[X]。Shan和H. Chen，物理学家修订版[j].中华医学杂志，1815（1993）。在考虑浮力效应的情况下，模拟了二维（2D）单个气泡的运动，其中气泡的拓扑结构以无因次Eotvos （Eo）和Morton (M)数为特征。在本研究中，采用了一种基于“有效浮力”的新方法，并被证明与期望的气泡形状变形相一致。这种方法扩大了气泡和液体之间可以模拟的有效密度差的范围。根据作用在气泡上的力的平衡，气泡可以由球形变形为椭球形，并在高Eo数时出现裙边。利用基于水平集方法的COMSOL Multiphysics进行了定性和定量验证的基准计算例。分别对1≤Eo≤100和3 × 10-6≤M≤2.73 × 10-3进行了仿真。在没有重力的情况下，通过满足拉普拉斯定律的模拟来检查界面张力。最后，对不同Eo和M值进行了基于终端上升速度和圆度的定量分析。我们的结果与文献中给出的理论形状制度和现有的模拟结果进行了比较。
This study describes the behavior of bubbles rising under gravity using the Shan and Chen-type multicomponent multiphase lattice Boltzmann method (LBM) [X. Shan and H. Chen, Phys. Rev. E47, 1815 (1993)]. Two-dimensional (2D) single bubble motions were simulated, considering the buoyancy effect for which the topology of the bubble was characterized by the nondimensional Eotvos (Eo), and Morton (M) numbers. In this study, a new approach based on the "effective buoyancy" was adopted and proven to be consistent with the expected bubble shape deformation. This approach expands the range of effective density differences between the bubble and the liquid that can be simulated. Based on the balance of forces acting on the bubble, it can deform from spherical to ellipsoidal shape with skirts appearing at high Eo number. A benchmark computational case for qualitative and quantitative validation was performed using COMSOL Multiphysics based on the level set method. Simulations were conducted for 1 ≤ Eo ≤ 100 and 3 × 10-6 ≤ M ≤ 2.73 × 10-3. Interfacial tension was checked through simulations without gravity, where Laplace's law was satisfied. Finally, quantitative analyses based on the terminal rise velocity and the degree of circularity was performed for various Eo and M values. Our results were compared with both the theoretical shape regimes given in literature and available simulation results.