There are three general approaches to solveing engineering problems:

• an experimental approach: a hardware rig or prototype, i.e., the full-scale object and/or its model, is manufactured and the experiments needed for designing the object are conducted with this hardware;

• a computational approach: the computations needed for designing the object are performed and their results are directly used for designing the object, without conducting any experiments;

• a computational-experimental approach combines computations and

experiments (with the manufactured full-scale object and/or its model) needed for designing the object, their sequence and contents depending on the solved problem, e.g. iterative procedures may be run.

Each of the first two approaches has advantages and disadvantages.The purely experimental approach, being properly conducted, does not require additional validations of the obtained results, but it is very expensive, even if it is realized on the object models, since testing facilities and hardware are required anyway. Moreover, if the object models are tested, the obtained results must be scaled to the full-scale object, so some computations are required anyway.