Corrosion can be accelerated by fluid flowing past a surface. The rotating cylinder electrode has practical applicability as a corrosion prediction tool for liquid flow. All that are needed are the appropriate relationships to interface different geometries. A review is presented of the relationships between mass transfer coefficient, fluid velocity, shear stress, and fluid properties in four geometries. The discussion results in equations that allow rotating (inner) cylinder electrode velocities to be chosen so that the mass transfer coefficients are equal to those in pipes, annuli, and wall jets. These equations can be used to establish approximate test conditions for the rotating cylinder electrode. The suggestion is made that equality of shear stress, while not always guaranteeing equality in mass transfer coefficients or corrosion rates, still seems to enable mass transfer influenced corrosion mechanisms to be duplicated by the rotating cylinder electrode. An extension to duplicating mass transfer plus erosion phenomena in the laboratory is hypothesized.