We study the instability induced by the gravity of a liquid layer hanging at the bottom of a horizontal cylinder and continuously supplied with "fresh" liquid. Depending on the flow rate, different regimes are observed: dripping, array of liquid columns, and liquid sheets. The column array exhibits collective behaviors that can be forced under well controlled conditions by driving the displacements of two boundary columns: optical mode (regular or "chaotic"), phase diffusion, and propagation of localized "dilation waves" of the pattern.

• Received 25 October 1993

DOI:https://doi.org/10.1103/PhysRevLett.74.538