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Aspect ratio effect on electroconvection in a suspended liquid crystal film with a rectangular boundary

Published online by Cambridge University Press:  31 August 2017

Xuefei Guo ,
Yongkang Le  and
Bochao Cao Open the ORCID record for Bochao Cao [Opens in a new window]
Xuefei Guo
Affiliation:
Department of Physics, Fudan University, Shanghai 200433, China
Yongkang Le
Affiliation:
Department of Physics, Fudan University, Shanghai 200433, China
Bochao Cao*
Affiliation:
Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433, China
*
†Email address for correspondence: [email protected]
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Abstract

The aspect ratio dependence of the electroconvection phenomenon in a suspended nematic liquid crystal film with a rectangular boundary is investigated. Two-dimensional global stability analysis is carried out on the coupled electrohydrodynamic system to calculate the instability boundary of the phenomenon for different aspect ratios. The calculated critical $R$ number (Rayleigh-like number) shows a rapidly decreasing trend in the low-aspect-ratio region (roughly $\unicode[STIX]{x1D6FE}<1.5$, where $\unicode[STIX]{x1D6FE}$ is defined as the aspect ratio of the film), and then the variation becomes slow until $\unicode[STIX]{x1D6FE}\approx 2.5$, where the critical $R$ number starts to increase slightly. Convective patterns of liquid films with different aspect ratios are also obtained from stability analysis and validated by particle image velocimetry measurement.

JFM classification

Instability: Instability Complex Fluids: Liquid crystals Interfacial Flows (free surface): Thin films
Type
Papers
Information
Journal of Fluid Mechanics , Volume 828 , 10 October 2017 , pp. 57 - 69
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Copyright
© 2017 Cambridge University Press 

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