RAYLEIGH INSTABILITY IN LIQUID-CRYSTAL JETS
Fel L.G., Zimmels Yoram

Received: November 14, 2003

PACS: 61.30.Hn, 68.03.Kn, 68.03.Cd

DJVU (181.3K)

PDF (405.5K)

Capillary instability of isothermal incompressible liquid-crystal (LC) jets is considered in the framework of linear hydrodynamics of uniaxial nematic LCs. The free boundary conditions with strong tangential anchoring of the director n at the surface are formulated in terms of the mean surface curvature \cH and the Gaussian surface curvature \cG. The static version of the capillary instability is shown to depend on the elasticity modulus K, the surface tension σ₀, and the radius r₀ of the LC jet, expressed in terms of the characteristic parameter . The problem of the capillary instability in LC jets is solved exactly and a dispersion relation, which reflects the effect of elasticity, is derived. It is shown that the increase of the elasticity modulus results in the decrease of both the cut-off wavenumber k and the disturbance growth rate s. This implies an enhanced stability of LC jets, compared to ordinary liquids. In the specific case where the hydrodynamic and orientational LC modes can be decoupled, the dispersion equation is given in a closed form.