Numerical study on the shear-induced lift force acting on a spherical bubble in aqueous surfactant solutions
Numerical study on the shear-induced lift force acting on a spherical bubble in aqueous surfactant solutions
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DOI：
10.1063/1.2911040
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发表时间：
2008-04
影响因子：
4.6
通讯作者：
Masato Fukuta;S. Takagi;Y. Matsumoto
中科院分区：
文献类型：
--
作者：
Masato Fukuta;S. Takagi;Y. Matsumoto
本文讨论了表面活性剂水溶液中单个气泡的运动。研究了线性剪切流中气泡表面被表面活性剂吸附污染，从而产生Marangoni效应时，气泡所受升力的变化。随着表面活性剂解吸速率常数的减小，朗缪尔数的增大，作用在球形气泡上的升力从清洁气泡的值减小到接近于零的程度。这种减小与表面上压力的非轴对称分布密切相关。与我们以前用轴对称死帽模型模拟的结果相比较，本模拟的升力系数比死帽模型的大。这是由于表面浓度的非轴对称分布造成的。这种分布的不对称性增强了表面压力分布的不对称性，最终导致了更大的切变诱导。
A single bubble motion in aqueous surfactant solutions is discussed in this paper. We focus on the change of the lift force acting on a bubble in a linear shear flow under the condition that the bubble surface is contaminated by surfactant adsorption which leads the Marangoni effect. With an increase of Langmuir number which corresponds to a decrease of desorption rate constant of surfactant, the lift force acting on a spherical bubble decreases from the value of a clean bubble to near zero. This reduction is significantly related to a nonaxisymmetric distribution of pressure on the surface. Comparing the present results with those of our previous simulations using an axisymmetric stagnant cap model, the lift coefficients in the present simulations show larger values than those of the stagnant cap model. This is due to a nonaxisymmetric distribution of surface concentration. This asymmetry of the distribution enhances the asymmetry of the surface pressure distribution, which ends up the larger shear-induc...