Aircraft gas-turbine engine design and analysis has represented a milestone discipline in the development of aviation. Actually the continuous demand from the civil and military sector for compactness, weight and cost reduction has pushed the research in the field towards the introduction of transonic axial-flow fans and compressors: thanks to the shock induced compression, they effectively provide high stage pressure ratio meeting at the same time the requirements of compactness and lightness. Precisely this technological necessity has driven the researchers to explore different simulation level to obtain high fidelity results and optimisation designs in acceptable timing and costs with industrial standards.