Numerical study of the Marangoni instability resulting in surface tension auto-oscillations: general regularities of the system evolution.
Numerical study of the Marangoni instability resulting in surface tension auto-oscillations: general regularities of the system evolution.
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导致表面张力自振荡的马兰戈尼不稳定性的数值研究：系统演化的一般规律。
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
D. Vollhardt
中科院分区：
文献类型：
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作者：
N. Kovalchuk;V. Kovalchuk;D. Vollhardt
对最近发现的表面张力自振荡现象的机理进行了理论研究，并对气-水界面下含表面活性剂液滴体系的Marangoni不稳定性进行了数值研究。模拟，流体力学方程的基础上，考虑到对流扩散和吸附的表面活性剂。该系统的行为是由非稳态浓度梯度是不均匀的表面上，以及在垂直于表面方向。最初，发生液滴材料的缓慢扩散溶解。表面活性剂的对流传递可以忽略不计，表面张力几乎保持恒定，系统参数在诱导期内变化相当缓慢。随着浓度梯度的增加，系统变得不稳定，导致对流速度、表面张力和表面吸附的跳跃。通过数值求解，得到了体相和表面的浓度和速度分布。比较了不同传质机理在不同阶段的贡献。
Theoretical studies are performed to explain the mechanism of surface tension auto-oscillations recently found. The Marangoni instability in a system containing a surfactant droplet under the air-water interface is investigated numerically. The simulations, based on the equations of fluid mechanics, take into account convective diffusion and adsorption of the surfactant. The behavior of the system is determined by nonstationary concentration gradients that are nonuniform on the surface as well as in the normal to the surface direction. Initially a slow diffusion dissolution of the drop material takes place. The convective transfer of the surfactant is negligible, the surface tension remains nearly constant and the system parameters change rather slowly during the induction period. With the increase of the concentration gradients the system becomes unstable, resulting in a jump in the convection velocity, surface tension, and adsorption on the surface. The concentration and velocity distributions in the bulk and on the surface are obtained from the numerical solution of the problem. The contributions of different mechanisms of the mass transfer are compared in different stages of the process.