Flow Structure and Deformation of Two Bubbles Rising Side by Side in a Quiescent Liquid
Flow Structure and Deformation of Two Bubbles Rising Side by Side in a Quiescent Liquid
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DOI：
10.3390/fluids6110390
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发表时间：
2021-11
期刊：
影响因子：
1.9
通讯作者：
Hiroaki Kusuno;T. Sanada
中科院分区：
文献类型：
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作者：
Hiroaki Kusuno;T. Sanada
在两个球形气泡并排上升的运动中，已知两个气泡在较高的雷诺数(Re=ρud/μ)下相互吸引。此外，球形气泡在一定条件下接吻和反弹；然而，可变形的气泡在没有接吻的情况下相互排斥。本文通过实验和数值模拟相结合的方法，给出了可变形气泡非接吻排斥的流动结构和形状。在实验分析中，我们用伽利莱数(Ga=ρg1/2d3/2/μ)和键数(Bo=ρgd2/σ)来组织气泡行为。在单个气泡不稳定的临界曲线附近，气泡相互排斥，没有接吻。缝隙内的曲率很大，类似于之字形的气泡。在数值分析中，由于位势相互作用，缝隙内赤道平面的速度较大，而由于表面产生的涡量增强，缝隙后面的速度则相反。此外，在相互作用的气泡后面出现了双线尾迹，这表明无论气泡是相互吸引还是相互排斥，旋转方向都是排斥的。在2D平面中，气泡后面的流线是从外到内。
In the motion of two spherical bubbles rising side by side, the bubbles are known to attract each other at a high Reynolds number (Re = ρUd/μ). Furthermore, spherical bubbles kiss and bounce under certain conditions; however, deformable bubbles repel each other without kissing. This paper experimentally and numerically presents the flow structures and shape of the nonkissing repulsion of deformable bubbles. For the experimental analysis, we organized bubble behaviors by Galilei number (Ga = ρg1/2d3/2/μ) and Bond number (Bo = ρgd2/σ). The bubbles repelled each other without kissing near the unstable critical curve of a single bubble. The curvature inside the gap, which is similar to the shape of a zigzag behavior bubble, was large. For the numerical analysis, the velocity of the equatorial plane inside the gap was larger due to the potential interaction, although the velocity behind was the opposite due to the strengthened vorticity generated at the surface. Furthermore, the double-threaded wake emerged behind the interacting bubbles, and it showed that the rotation direction was repulsion regardless of whether the bubbles attracted or repelled each other. The streamline behind the bubbles in the 2D plane was from the outside to the inside.