Linear stability analysis of bubble-induced convection in a horizontal liquid layer
Linear stability analysis of bubble-induced convection in a horizontal liquid layer
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水平液层中气泡诱发对流的线性稳定性分析
DOI：
10.1103/physreve.102.053102
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发表时间：
2020
影响因子：
2.4
通讯作者：
Y.Murai
中科院分区：
文献类型：
--
作者：
K.Nakamura;H.N.Yoshikawa;Y.Tasaka;Y.Murai
我们用线性分析的方法研究了水平液层在底部注入气泡的情况下的稳定性。假设注入在空间上均匀，在时间上恒定。由于阿基米德浮力，注入的气泡在液层中上升，并从液层的顶部自由表面喷出。将这一两相流动系统模拟为两个相互穿透的液气连续介质，我们发现在大的气体流量下，均匀向上的气体流动变得不稳定。我们确定了这种均相-非均相区域转变的临界条件，表明临界模式是由静止对流辊组成的，无论是多层还是全层，取决于液体粘度、气泡半径和液层厚度。通过考察从底部到扰动流动的能量传递，我们表明液体对流运动是由非均匀分布气泡上的浮力驱动的。我们还发现，对气泡的升力通过使靠近底壁的气泡分布均匀而具有显著的稳定作用。
We investigate with a linear analysis the stability of a horizontal liquid layer subjected to injection of gas bubbles through a bottom wall. The injection is assumed uniform in space and constant in time. Injected bubbles ascend in the liquid layer due to the Archimedean buoyancy force and are ejected from the top free surface of the liquid layer. Modeling this two-phase flow system as two interpenetrating liquid and gas continua, we show that homogeneous upward gas flows become unstable at large gas fluxes. We determine the critical conditions of this homogeneous-heterogeneous regime transition and show that the critical modes are made of stationary convection rolls, either multi- or whole-layered depending on liquid viscosity, the radius of bubbles, and the thickness of liquid layer. By examining the energy transfer from base to perturbation flows, we indicate that liquid convective motion is driven by the buoyancy on heterogeneously distributed bubbles. We also reveal that the lift forces on bubbles have significant stabilizing effects by homogenizing bubble distribution close to the bottom wall.