Theoretical analysis of the stability of shear flow of nematic liquid crystals with a positive Leslie viscosity α3

Carlsson, Tomas; Högfors, Christian

doi:10.1016/j.jnnfm.2003.02.002

Cited by 2 publications

(1 citation statement)

References 28 publications

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“…In this case, the director may tend to leave the plane of shear. However, recent studies 37 have shown that a physically realisable solution for shear flow of a non-flow-aligning nematic liquid crystal with the director within the plane of shear is possible when the shear rate is low enough and the boundary conditions are appropriate. In such a case, the present analysis follows through with only minor differences.…”

Section: Discussionmentioning

confidence: 99%

Shear-driven and pressure-driven flow of a nematic liquid crystal in a slowly varying channel

et al. 2006

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Motivated by the industrially important processes of blade coating and cavity filling of liquid crystalline materials, we consider steady, two-dimensional shear-driven (Couette) and pressure-driven (plane Poiseuille) flow of a thin film of a nematic liquid crystal in the slowly varying channel formed between a fixed blade of prescribed shape and a planar substrate. Specifically, blade coating motivates the study of shear-driven flow due to the motion of the substrate parallel to itself with constant velocity, while cavity filling motivates the study of pressure-driven flow due to an imposed pressure drop. We use a combination of analytical and numerical techniques to analyse the Ericksen--Leslie equations governing the fluid velocity and pressure and the director orientation in cases when both the aspect ratio of the channel and the distortion of the director field are small. We demonstrate a variety of flow and director-orientation patterns occurring in different parameter regimes. In the limit of weak flow effects flow alignment does not occur and the appropriate solution of the governing equations is found explicitly. In the limit of strong flow effects flow alignment occurs and orientational boundary layers exist near the substrate and near the blade, and in addition, an orientational internal layer may also exist within which the director orientation changes from +theta_0 to -theta_0 where theta_0 is the flow-alignment angle

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Section: Discussionmentioning

confidence: 99%

Shear-driven and pressure-driven flow of a nematic liquid crystal in a slowly varying channel

et al. 2006

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Flow alignment phenomena in liquid crystals studied by molecular dynamics simulation

Sarman

Laaksonen²

2009

The Journal of Chemical Physics

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The flow alignment of a nematic liquid crystal has been studied as a function of temperature, beginning at high temperature in the nematic phase and down to the nematic-smectic A phase transition. The alignment angle is obtained by estimating the twist viscosities by nonequilibrium molecular dynamics (NEMD) methods. These estimates are cross-checked by evaluating the corresponding equilibrium fluctuation relations. As a further comparison, shear flow simulations are carried out by application of the SLLOD equations of motion (so named because of their close relationship to the Doll's equation of motion, which can be derived from the Doll's tensor Hamiltonian), whereby the alignment angle is obtained directly. All these methods give consistent results for the alignment angle. At low temperatures near the nematic-smectic A transition the system becomes flow unstable. In this region the alignment angle has been calculated as a function of time.

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Theoretical analysis of the stability of shear flow of nematic liquid crystals with a positive Leslie viscosity α3

Cited by 2 publications

References 28 publications

Shear-driven and pressure-driven flow of a nematic liquid crystal in a slowly varying channel

Shear-driven and pressure-driven flow of a nematic liquid crystal in a slowly varying channel

Flow alignment phenomena in liquid crystals studied by molecular dynamics simulation

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