Applied Mathematics and Mechanics (English Edition) ›› 2011, Vol. 2 ›› Issue (32): 133-140.doi: https://doi.org/10.1007/s10483-011-1400-x

• Articles •    下一篇

Linear instability of ultra-thin liquid films flowing down cylindrical fibre

赵陆海波 胡国辉 周哲玮   

  1. Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, P. R. China
  • 收稿日期:2010-10-06 修回日期:2010-12-07 出版日期:2011-01-24 发布日期:2011-01-24

Linear instability of ultra-thin liquid films flowing down cylindrical fibre

 ZHAO Lu-Hai-Bo, HU Guo-Hui, ZHOU Zhe-Wei   

  1. Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, P. R. China
  • Received:2010-10-06 Revised:2010-12-07 Online:2011-01-24 Published:2011-01-24

摘要: The stability characteristics of an ultra-thin layer of a viscous liquid flowing down a cylindrical fibre are investigated by a linear theory. The film with the thickness less than 100 nm is driven by an external force and under the influence of the van der Waals forces. The results show that, when the relative film thickness decreases, the curvature of the fibre depresses the development of the linear perturbations, whereas the van der Waals forces promote the instabilities. This competition results in a non-monotonous dependence of the growth rate on the relative film thickness. The critical curves are also obtained to describe the transition from the absolute instability to the convective instability, indicating that the van der Waals forces can enlarge the absolutely unstable region. Furthermore, the surface tension can cause the development of the absolute instability, whereas the external force has an opposite effect.

Abstract: The stability characteristics of an ultra-thin layer of a viscous liquid flowing down a cylindrical fibre are investigated by a linear theory. The film with the thickness less than 100 nm is driven by an external force and under the influence of the van der Waals forces. The results show that, when the relative film thickness decreases, the curvature of the fibre depresses the development of the linear perturbations, whereas the van der Waals forces promote the instabilities. This competition results in a non-monotonous dependence of the growth rate on the relative film thickness. The critical curves are also obtained to describe the transition from the absolute instability to the convective instability, indicating that the van der Waals forces can enlarge the absolutely unstable region. Furthermore, the surface tension can cause the development of the absolute instability, whereas the external force has an opposite effect.

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