Fingering Instability of Gravity Currents in Thin-Layer Electrochemical Deposition

A hydrodynamic instability has been observed in quasi-two-dimensional electrochemical deposition experiments in which the electrochemical cell is inclined with respect to the horizontal. Gravity-driven flows generated at both anode and cathode become unstable and form a pattern of fingers when the anode is uphill from the cathode. I report measurements of the onset wavelength and development of the pattern, and discuss ways in which the growth of the metal aggregate at the cathode interacts with the flow and its instability.