Towards a phenomenological model on the deformation and orientation dynamics of finite-sized bubbles in both quiescent and turbulent media
Towards a phenomenological model on the deformation and orientation dynamics of finite-sized bubbles in both quiescent and turbulent media
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DOI：
10.1017/jfm.2021.390
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发表时间：
2021-06
影响因子：
3.7
通讯作者：
A. U. M. Masuk;Yinghe Qi;Ashwanth K. R. Salibindla;R. Ni
中科院分区：
文献类型：
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作者：
A. U. M. Masuk;Yinghe Qi;Ashwanth K. R. Salibindla;R. Ni
摘要提出了一个描述静止和湍流水介质中有限尺寸气泡变形和取向动力学的唯象模型。该模型扩展并概括了由Maffettone & Minale（J. Non-Newtonian Fluid Mech.，第78卷，1998年，pp. 227-241），进入高雷诺数状态，其中气泡变形由流动惯性主导。通过故意划分流动惯性从滑移速度和速度梯度的贡献，一个新的配方气泡变形的构造和验证对两个实验，旨在捕捉气泡的变形和取向的动态，同时与两种类型的周围流。各变形机制的相对重要性通过其各自的无量纲系数来衡量，无需多变量拟合，通过多个实验约束即可独立地进行分离和评价，结果与模型预测吻合较好。所获得的系数意味着，气泡重新定向，通过身体旋转，因为它们在水中上升，在休息，但通过变形沿着不同的方向在湍流。最后，我们提供了建议，如何实现所提出的框架，在模拟中的可变形气泡/液滴的动态特性。
Abstract A phenomenological model is proposed to describe the deformation and orientation dynamics of finite-sized bubbles in both quiescent and turbulent aqueous media. This model extends and generalizes a previous work that is limited to only the viscous deformation of neutrally buoyant droplets, conducted by Maffettone & Minale (J. Non-Newtonian Fluid Mech., vol. 78, 1998, pp. 227–241), into a high Reynolds number regime where the bubble deformation is dominated by flow inertia. By deliberately dividing flow inertia into contributions from the slip velocity and velocity gradients, a new formulation for bubble deformation is constructed and validated against two experiments designed to capture the deformation and orientation dynamics of bubbles simultaneously with two types of surrounding flows. The relative importance of each deformation mechanism is measured by its respective dimensionless coefficient, which can be isolated and evaluated independently through several experimental constraints without multi-variable fitting, and the results agree with the model predictions well. The acquired coefficients imply that bubbles reorient through body rotation as they rise in water at rest but through deformation along a different direction in turbulence. Finally, we provide suggestions on how to implement the proposed framework for characterizing the dynamics of deformable bubbles/drops in simulations.