Enhanced corrosion frequently occurs at surface disturbances introduced by fittings, valves, weld beads and other forms of geometric changes. Such flow enhanced corrosion is often mass transfer controlled due to increased species transport in the regions of disturbed flow.Towards a better understanding of such phenomena which are linked to electrochemical aspects of the fluid and surface interaction, a stepped rotating electrode has been developed consisting of two symmetrically placed backward facing steps on a rotating cylinder. Flow visualization studies using sulphuric acid vapor in air and surface dye dissolution, have been used together with surface heat and mass transfer measurements and DNS to help characterize the flow.While the classical reattachment behind a backward facing step is indicatd by the results. DNS data have led to a new understanding of the reattaching flow and its highly unstable nature.The high turbulence generated by this flow is readily seen and differences between mean and fluctuating wall shear stresses are quantified. The observed flow patterns corelate with surface heat and mass transfer measurements. Findings suggest that the new stepped rotating electrode will be a convenient and useful tool for further flow related corrosion studies.