For each V&V case presented in this manual, the comparison between Rocky results and the reference data (from analytical expressions or experiments) is done by means of absolute and relative errors calculations.

The absolute error is defined as the difference between the value calculated by Rocky and the reference value of a quantity that is being compared. For example, imagine that we are interested in knowing the velocity of a particle in a certain time step and is the value calculated by Rocky. In this case, the absolute error can be calculated using the formula , where is the reference value (analytical or experimental).

The relative error is defined as the ratio of the absolute error to the reference value. Thus, the relative error gives an indication of how close the Rocky results are to the actual values that we are considering as reference. Using the same example, we can calculate the relative error for the velocity using the formula . Important: The relative errors are dimensionless; within this manual we multiply the relative errors by 100 to express them as percentages.

It is important to state that in this manual, for the validation cases where the reference values come from experiments, we are considering the experimental mean values for the errors calculation and additional comments are added when we deem necessary.

As a complementary analysis, for the V&V cases that converge to a final constant or stable value, a table with each target value and the respective solution ratio is presented in order to show the level of correlation achieved by the results.