Autori: Iuliana Oprea, Gerhard Dangelmayr

Editorial: European Journal of Mechanics - B/Fluids, 27, 2008.

Rezumat:

In this paper we present the results of a bifurcation study of the weak electrolyte model for nematic electroconvection, for values
of the parameters including experimentally measured values of the nematic I52. The linear stability analysis shows the existence of
primary bifurcations of Hopf type, involving normal as well as oblique rolls. The weakly nonlinear analysis is performed using four
globally coupled complex Ginzburg–Landau equations for the waves’ envelopes. If spatial variations are ignored, these equations
reduce to the normal form for a Hopf bifurcation with O(2) × O(2) symmetry. A rich variety of stable waves, as well as more complex spatiotemporal dynamics is predicted at onset. A temporal period doubling route to spatiotemporal chaos, corresponding to a period doubling cascade towards a chaotic attractor in the normal form, is identified. Eckhaus stability boundaries for travelling
waves are also determined. The methods developed in this paper provide a systematic investigation of nonlinear physical mechanisms generating the patterns observed experimentally, and can be generalized to any wo-dimensional anisotropic systems with translational and reflectional symmetry

Cuvinte cheie: Nematic electroconvection; Weak electrolyte model; Amplitude equations; Hopf bifurcation; Spatiotemporal chaos; Eckhaus stability