This work reports a numerical study of mixing in stratified fluids induced by the motion of monodispersed swarm of bubbles in a thin gap. Simulations are run for void fractions between 3.35 strength of stratification is varied by changing the Froude number between 4.5 to 12.74. The confinement prevents turbulent production and mixing occurs primarily due to transport by the bubble wake. We observe a zigzag motion of the bubbles attributed to the periodic vortex shedding behind the bubbles. We report the formation of horizontal clusters and establish a direct correlation between the size of clusters and the rise velocity of the bubbles. We report an increase in the buoyancy flux across the isopycnals as the void fraction increases. The fraction of energy production due to the buoyancy flux increases with the strength of stratification, giving rise to a higher mixing efficiency.

中文翻译：

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在细小的间隙中上升的气泡引起分层流体中的混合

这项工作报告了由细小间隙中的气泡的单分散群运动引起的分层流体混合的数值研究。通过将弗劳德数在4.5到12.74之间变化，可以模拟在3.35之间的空隙率。该限制防止湍流产生，并且主要由于气泡尾流的运输而发生混合。我们观察到气泡的锯齿形运动是由于气泡后面的周期性涡流脱落而引起的。我们报告了水平簇的形成，并建立了簇的大小与气泡上升速度之间的直接相关性。我们报告，随着空隙率的增加，跨等深线的浮力通量增加。浮力通量所产生的能量分数随分层强度的增加而增加，