Abstract
We rigorously derive from first principles the generic Landau amplitude equation that describes the primary bifurcation in electrically driven convection. Our model accurately represents the experimental system: a weakly conducting, submicron thick liquid crystal film suspended between concentric circular electrodes and driven by an applied voltage between its inner and outer edges. We explicitly calculate the coefficient of the leading cubic nonlinearity and systematically study its dependence on the system’s geometrical and material parameters. The radius ratio quantifies the film’s geometry while a dimensionless number , similar to the Prandtl number, fixes the ratio of the fluid’s electrical and viscous relaxation times. Our calculations show that for fixed , is a decreasing function of , as becomes smaller, and is nearly constant for . As , . We find that is a nontrivial and discontinuous function of . We show that the discontinuities occur at codimension-two points that are accessed by varying .
- Received 10 November 2004
DOI:https://doi.org/10.1103/PhysRevE.72.036211
©2005 American Physical Society