Complex Structures in Rotating Systems
Hermann Riecke
Northwestern University
Convection has served
as an excellent system for the study of pattern formation. By applying
rotation to the system it becomes non-variational even right at onset allowing
for complex dynamics. I will briefly review some aspects of the impact
of rotation on roll-type convection patterns focussing on the Kueppers-Lortz
instability. Then I will discuss our recent results on the effect of rotation
on hexagonal planforms. For steady weakly nonlinear hexagons we find spatio-temporal
chaos triggered by induced nucleation. We show that oscillating hexagons
are typically described by the two-dimensional complex Ginzburg-Landau
equation in a regime of defect chaos. Using the Navier-Stokes equations
we find whirling chaos and study the statistics of defects in the pattern.