Photoacoustic depth profiling of the thermal conductivity of an inhomogeneously aligned liquid crystal at a free surface

1995 ◽  
Vol 78 (5) ◽  
pp. 3096-3101 ◽  
Author(s):  
C. Glorieux ◽  
Z. Bozoki ◽  
J. Fivez ◽  
J. Thoen
Keyword(s):  
Thermal Conductivity ◽  
Free Surface ◽  
Liquid Crystal ◽  
Depth Profiling

Thermal conductivity of the nematic liquid crystal 4-n-pentyl-4’-cyanobiphenyl

1994 ◽  
Vol 49 (1) ◽  
pp. 545-553 ◽  
Author(s):  
Guenter Ahlers ◽  
David S. Cannell ◽  
Lars Inge Berge ◽  
Shinichi Sakurai
Keyword(s):  
Thermal Conductivity ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal

Electrohydrodynamic Flow in Thick Liquid Crystal Cells

1989 ◽  
Vol 177 ◽  
Author(s):  
David H. Van Winkle ◽  
Jit Gurung ◽  
Rand Biggers
Keyword(s):  
Thermal Conductivity ◽  
Liquid Crystal ◽  
Thermal Transport ◽  
Room Temperature ◽  
Liquid Crystal Cell ◽  
Optical Observations ◽  
Constant Voltage ◽  
Maximum Enhancement ◽  
Flowing Liquid ◽  
Crystal Cells

ABSTRACTThe 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).

Three-dimensional coating flow of nematic liquid crystal on an inclined substrate

2015 ◽  
Vol 26 (5) ◽  
pp. 647-669 ◽  
Author(s):  
M. A. LAM ◽  
L. J. CUMMINGS ◽  
T.-S. LIN ◽  
L. KONDIC
Keyword(s):  
Free Surface ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Nonlinear Partial Differential Equation ◽  
Three Dimensional ◽  
Travelling Wave ◽  
Linear Stability Theory ◽  
Newtonian Flow ◽  
Surface Evolution ◽  
Coating Flow

We consider a coating flow of nematic liquid crystal (NLC) fluid film on an inclined substrate. Exploiting the small aspect ratio in the geometry of interest, a fourth-order nonlinear partial differential equation is used to model the free surface evolution. Particular attention is paid to the interplay between the bulk elasticity and the anchoring conditions at the substrate and free surface. Previous results have shown that there exist two-dimensional travelling wave solutions that translate down the substrate. In contrast to the analogous Newtonian flow, such solutions may be unstable to streamwise perturbations. Extending well-known results for Newtonian flow, we analyse the stability of the front with respect to transverse perturbations. Using full numerical simulations, we validate the linear stability theory and present examples of downslope flow of nematic liquid crystal in the presence of both transverse and streamwise instabilities.

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