Abstract
We have quantitatively investigated the parity-breaking bifurcation in a liquid column pattern with periodic boundary conditions formed below an overflowing dish. For high enough viscosity homogeneous global drifting states can be stabilized within a large range of wavelengths. Data are analyzed in terms of coupled phase and amplitude equations and show that the bifurcation to a global drifting state is supercritical, the flow rate and phase gradient behaving as effective control parameters. The wavelength dependence shows that new non-linearities must be added to the usual model. We also identify at large flow rate a regime of spatio-temporal chaos that mixes oscillations, drifts, coalescences and nucleations of columns.