Lift and drag coefficients of deformable bubbles in intense turbulence determined from bubble rise velocity
Lift and drag coefficients of deformable bubbles in intense turbulence determined from bubble rise velocity
复制标题
DOI：
10.1017/jfm.2020.244
复制
发表时间：
2020-07-10
影响因子：
3.7
通讯作者：
Ni Rui
中科院分区：
文献类型：
--
作者：
Salibindla, Ashwanth K. R.;Masuk, Ashik Ullah Mohammad;Ni Rui
我们通过实验研究了能量耗散率为 的高湍流中有限尺寸气泡的上升速度。与之前报道的弱湍流中上升速度下降 30-40% 相比（韦伯数 () 远小于 Eotvos 数 ();），强烈湍流中的气泡上升速度显示出令人惊讶的新行为：与静止介质中的上升速度相比，突然从慢一个数量级突然转变为快两倍。当从低于 1 增加到高于 1 时，就会发生这种转变，强调了湍流引起的变形所发挥的关键作用。我们还建立了一个基于气泡涡流耦合的模型，结果不仅与我们在强湍流中的数据非常一致，而且与其他关于弱湍流的工作也非常一致。该模型还帮助我们在现场提取各种雷诺数的强烈湍流中气泡的升力和阻力系数。
We experimentally investigate the rise velocity of finite-sized bubbles in turbulence with a high energy dissipation rate of . In contrast to a 30-40 % reduction in rise velocity previously reported in weak turbulence (the Weber number () is much smaller than the Eotvos number (); ), the bubble rise velocity in intense turbulence shows a surprising new behaviour: an abrupt transition from an order of magnitude slower to a factor of two faster than rising in an otherwise quiescent medium. This transition occurs when increases from below one to above one, underscoring the key role played by the turbulence-induced deformation. We also formulate a model based on bubble-eddy coupling, and the results show an excellent agreement with not only our data in intense turbulence but also other works on weak turbulence. The model also helps us to extract the lift and drag coefficients of bubbles in intense turbulence for a wide range of and Reynolds numbers in situ.