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Electrohydrodynamic Flow in Thick Liquid Crystal Cells

Published online by Cambridge University Press:  21 February 2011

David H. Van Winkle ,
Jit Gurung  and
Rand Biggers
David H. Van Winkle
Affiliation:
Department of Physics and Center for Materials Research and Technology, The Florida State University, Tallahassee, Florida 32306-3016
Jit Gurung
Affiliation:
Box 4026, Davidson College, Davidson, NC 28036
Rand Biggers
Affiliation:
Code 2110, Naval Coastal Systems Center, Panama City, FL 32407
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Abstract

The thermal transport across a thick (0.66 cm) liquid crystal cell has been measured versus applied ac voltage and frequency. These measurements are correlated with the optically observed onset of flow and turbulence in cells as identical as practicable to those used for the thermal transport measurements. In addition, the measurements are compared with reported observations in thin cells. The thermal transport across the liquid crystal is characterized by an effective thermal conductivity Kf. It was found that Kf increases with increasing frequency, at constant voltage, to a maximum enhancement at about 40 Hz at room temperature. Optical observations on thick cells indicate that dynamic columnar domains of flowing liquid crystal are the primary mode of heat transport, as determined by correlating the structure and characteristic lifetime of such domains as a function of voltage and frequency. Optical observations at low voltages suggest that Williams Domains do not exist in these thick cells, and that all observed responses are functions of electric field strength, not applied voltage (as in thin Williams Domain cells).

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 177: Symposium V – Macromolecular Liquids , 1989 , 311
Copyright
Copyright © Materials Research Society 1990

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