Numerical modelling corrosion rate

Figure 5 shows the predicted vertical current densities 100pm above the solid model. It can be seen from figure 4 that this is a degraded representation but nevertheless a source of validation. A coupled approach to SVET experimentation and numerical prediction also considers this [15], Figure 5 shows a marked decrease in the frequency of anodic instances from [3] and it is apparent that the reduction in eutectic size corresponds to an increase in corrosion rate. The intensity of the anodic events is now more consistent within simulations and observation. 

Most models focus on specific forms of corrosion and hence cannot be used in all environments with equal confidence. These models are usually fashioned and tweaked to either fit as accurately as possible to field data and results (which in themselves may not be entirely accurate for several reasons) or to fit results of laboratory tests, which may be similar in trend but frequently differ in value from observations made in the field. Neither model attempts to use a combination of numerical lab data and knowledge and heuristic field data and experience to make a prediction. Another approach to the corrosion prediction problem is to develop a model that does not result in a single equation for the whole domain of the parameter value but rather focuses on utilizing a set of equations to extract a prediction from data values that are as similar as possible to those of the problem. This reduces the domain of generalization of the equations since for each new problem, a new set of data values (which are similar to those of the problem) are used to extract a corrosion rate value. 

Despite the several mathematical models being developed for describing corrosion problems and their solutions, each model has its own degree of accuracy, which depends on the chosen variables and conditions, and numerical method for determining relevant parameters that describe a particular corrosion phenomenon. Comprehensive reviews of models for describing a particular problem, such as crevice cathodic protection, pitting growth rate, current and potential attenuation are available in the literature [2,3,18,25-32]. 

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