Abstract
Physical scale modelling (PSM) is an experimental technology that has been used to evaluate and design shipboard impressed current cathodic protection (ICCP) systems. PSM is also a preferred tool used for validating numerical modelling results owing to the well-controlled conditions in PSM experiments. However, one issue in using PSM for the validation of numerical modelling results is the lack of information on the actual polarization behavior of the cathodes on a model hull during PSM experiments. Consequently, the polarization curve data used as boundary conditions in numerical modeling trials is usually different from the polarization behavior of the cathodes in PSM experiments. This difference can result in a discrepancy between the numerical modelling and the PSM results that is difficult to separate from other numerical errors.
A discrete area current control (DACC) technique was developed in a previous ICCP PSM study to simulate the polarization behavior of a propeller material under various conditions. The present study extended the DACC technique to simulating the polarization curve behavior of multiple discrete cathodes on a model hull. The application of the DACC technique also made it possible for both the PSM and numerical modelling trials to use the same sets of polarization curve data as inputs or as boundaries in the validation studies. This paper demonstrates the use of the DACC technique to simulate the polarization behaviors of a propeller material and three paint damage patches. The PSM results obtained under different polarization behaviors of propeller and hull materials are also used to validate the numerical modelling results obtained under the same polarization conditions.
