Abstract In this paper, the highly deformed bubbles produced in the regime of bubbling with coalescence are studied systematically, starting from their formation up to their collapse dynamics. We investigate the bubbling dynamics by performing experiments with various liquids (ultrapure water and silicone fluids), gas flow rates (5–300 ml/min) and nozzle radii (0.18–0.55 mm). The evolution of the coalescing process is analyzed in detail, differentiating among four phases: liquid film drainage, neck formation, wave propagation along the bubble surface and bubble detachment. A phase diagram for coaxial coalescence and no coalescence is established in terms of the Weber (to describe the effects of inertia) and the Morton number numbers (to describe the effects of liquid property). Scaling arguments show that the coalescing dynamics is driven by inertia–capillary and viscosity can be neglected. We then present the interesting experimental investigation of large and elongated bubbles just after pinch-off. We deduce the dependence of the geometrical properties of these highly deformed bubbles on the bubbling conditions and a simple model is derived. Finally, we explore the dynamics of the inertial liquid jets arising from the collapse of such highly deformed bubbles. Regardless of the details of the collapse process, we propose a simple scaling law for the jet velocity and unravel the intricate roles of bubble geometry and liquid parameters.

中文翻译：

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同轴聚结产生的高度变形气泡行为的实验研究

摘要 在本文中，系统地研究了在起泡和聚结状态下产生的高度变形的气泡，从它们的形成到它们的坍塌动力学。我们通过对各种液体（超纯水和硅油）、气体流速（5-300 毫升/分钟）和喷嘴半径（0.18-0.55 毫米）进行实验来研究起泡动力学。详细分析了聚结过程的演变，区分了四个阶段：液膜排放、颈部形成、沿气泡表面的波传播和气泡脱离。根据韦伯（描述惯性的影响）和莫顿数（描述液体性质的影响）建立了同轴聚结和不聚结的相图。缩放参数表明聚结动力学是由惯性-毛细管驱动的，粘度可以忽略不计。然后，我们展示了在夹断后对大而细长的气泡进行的有趣的实验研究。我们推导出这些高度变形气泡的几何特性对冒泡条件的依赖性，并推导出一个简单的模型。最后，我们探索了由这种高度变形的气泡坍塌引起的惯性液体射流的动力学。无论崩溃过程的细节如何，我们都提出了一个简单的射流速度缩放定律，并阐明了气泡几何形状和液体参数的复杂作用。我们推导出这些高度变形气泡的几何特性对冒泡条件的依赖性，并推导出一个简单的模型。最后，我们探索了由这种高度变形的气泡坍塌引起的惯性液体射流的动力学。无论崩溃过程的细节如何，我们都提出了一个简单的射流速度缩放定律，并阐明了气泡几何形状和液体参数的复杂作用。我们推导出这些高度变形气泡的几何特性对冒泡条件的依赖性，并推导出一个简单的模型。最后，我们探索了由这种高度变形的气泡坍塌引起的惯性液体射流的动力学。无论坍缩过程的细节如何，我们都提出了一个简单的射流速度缩放定律，并阐明了气泡几何形状和液体参数的复杂作用。