A review of some complex flow behaviour and related models in different types of turbo-machines

Unsteady flow character is evident; transient regimes may also be considered in some cases. Nowadays, N.S calculations has the advantage to give detailed information of the flow in any kind of locations. However, this big amount of information does not give indication on what geometrical modification will improve the flow characteristics and machine performances. Perform the use of good models in also a key point. Several level of approximation already exists depending on the kind of information that has to be reached.A better insight in needed, based on theoretical consideration in order to understand and identify flow mechanism is given thereafter.