Lift force acting on a pair of clean bubbles rising in-line
Lift force acting on a pair of clean bubbles rising in-line
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DOI：
10.1063/1.5100183
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发表时间：
2019-07
影响因子：
4.6
通讯作者：
Hiroaki Kusuno;Hiroya Yamamoto;T. Sanada
中科院分区：
文献类型：
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作者：
Hiroaki Kusuno;Hiroya Yamamoto;T. Sanada
在本研究中，我们通过实验观察了一对最初排成一行的气泡的运动，特别关注中间雷诺数情况，即 20 < Re < 60。我们观察了不同雷诺数下的三种类型的运动。在低雷诺数 (Re < 20) 下，尾随气泡与前导气泡发生碰撞，就像一对刚性球体一样。在高雷诺数 (100 < Re) 下，尾随气泡从连接两个气泡的原始垂直线移出。在中间雷诺数 (20 < Re < 60) 下，气泡尺寸的微小差异会影响运动。当前导气泡大于或等于尾随气泡时，尾随气泡首先接近前导气泡，然后由于升力而从初始垂直线移出。当前导气泡小于后导气泡时，后导气泡首先接近前导气泡，然后排斥力作用在两个气泡上，使它们都从垂直线向相反的方向移出。这些运动归因于两个效应，第一个是气泡之间短距离的潜在效应，第二个是领先气泡的尾流。在本研究中，我们通过实验观察了一对最初排成一行的气泡的运动，特别关注中间雷诺数情况，即 20 < Re < 60。我们观察到了不同雷诺数下的三种类型的运动。在低雷诺数 (Re < 20) 下，尾随气泡与前导气泡发生碰撞，就像一对刚性球体一样。在高雷诺数 (100 < Re) 下，尾随气泡从连接两个气泡的原始垂直线移出。在中间雷诺数 (20 < Re < 60) 下，气泡尺寸的微小差异会影响运动。当前导气泡大于或等于尾随气泡时，尾随气泡首先接近前导气泡，然后由于升力而从初始垂直线移出。当前导气泡小于后导气泡时，后导气泡首先接近前导气泡，然后排斥力作用在两个气泡上，使它们都从垂直方向移出...
In this study, we experimentally observed the motion of a pair of bubbles initially positioned in line, especially focusing on the intermediate Reynolds number case, i.e., 20 < Re < 60. We observed three types of motion at different Reynolds numbers. At a low Reynolds number (Re < 20), the trailing bubble collided with the leading bubble like a pair of rigid spheres. At a high Reynolds number (100 < Re), the trailing bubble moved out from the original vertical line joining the two bubbles. At intermediate Reynolds numbers (20 < Re < 60), small differences in bubble size affected the motion. When the leading bubble was larger than or equal to the trailing bubble, the trailing bubble first approached the leading bubble and later moved out from the initial vertical line owing to a lift force. When the leading bubble was smaller than the trailing bubble, the trailing bubble first approached the leading bubble, and then a repulsive force acted on both bubbles so that both of them moved out from the vertical line in opposite directions. These motions are attributed to two effects, the first is potential effects at short distance between bubbles, and the second is the wake of the leading bubble.In this study, we experimentally observed the motion of a pair of bubbles initially positioned in line, especially focusing on the intermediate Reynolds number case, i.e., 20 < Re < 60. We observed three types of motion at different Reynolds numbers. At a low Reynolds number (Re < 20), the trailing bubble collided with the leading bubble like a pair of rigid spheres. At a high Reynolds number (100 < Re), the trailing bubble moved out from the original vertical line joining the two bubbles. At intermediate Reynolds numbers (20 < Re < 60), small differences in bubble size affected the motion. When the leading bubble was larger than or equal to the trailing bubble, the trailing bubble first approached the leading bubble and later moved out from the initial vertical line owing to a lift force. When the leading bubble was smaller than the trailing bubble, the trailing bubble first approached the leading bubble, and then a repulsive force acted on both bubbles so that both of them moved out from the vertical li...