6. Conclusion

An analysis of the state-of-the-art in methods for calculating flows in incompressible fluid machines shows that many effects, such as unsteadiness due to interaction effects between stationary and moving parts, are beginning to be taken into account, but only by means of tricks that cannot convey all the spatial and temporal information. Furthermore, the correct prediction of losses due to flow viscosity remains closely linked to turbulence modelling. The effects of cavitation are currently considered globally, and do not yet reflect the unsteady effects intrinsic to this type of flow, which is inherently compressible due to the mixing of phases.

Despite all these imperfections and approximations, these methods have made considerable progress in recent years. They have become indispensable tools for design offices in designing and improving machine performance....