The rotating cylinder electrode configuration is one of the most used electrochemical configurations for electrochemical processes study. It is often used with turbulent flow regime for industrial application Such as intensive corrosion or electro deposition processes. It can also be used for laminar regimes but in this case it can appear superposition between forced convection and natural free convection. This natural free convection is generally due to density gradient from electrode to bulk, due to electro deposition or to evolving bubbles. The hydrodynamic regime is then said mixed. There is few knowledge concerning the mixed hydrodynamic and the main goal of the present work is to show the qualitative and quantitative effects and differences between purely forced convective flow and purely free natural flow. (c) 2005 Elsevier Ltd. All rights reserved.