Dynamics of a liquid column array under periodic boundary conditions

We investigate the dynamics of a pattern of liquid columns formed below a circular fountain. Traveling domains consisting of drifting asymmetrical cells are forced and quantitatively studied. We provide evidence of a unique propagation velocity of the domain walls, which increases with the flow rate but depends on neither the number of moving columns nor the fluid viscosity. Similar to the "printer's instability," this velocity is proportional to a natural velocity formed from the static wavelength and the frequency of localized oscillations of the column position.