The calculation of fully three dimensional flow through any type of turbomachine blade row

Various approximation levels, enabling the simplification of the full system of Reynolds averaged Navier-Stokes equations, are presented. The latter are considered as the highest level model of flow description and depend heavily on the turbulence models. Viscous approximations such as the thin shear layer and the parabolized Navier-Stokes models are discussed. The disturbed loss model, applied in turbomachinery applications, is intermediate between the viscous and inviscid approximations. The Euler equations, rotational flow models and the simplest potential flow are further discussed and their limitations are printed out.