The research on linear cascades in Blow down Wind Tunnel, is generally addressed to the evaluation of the influence of several different operational conditions (Mach number, incidence angle, stagger angle, cascade solidity, etc.) on the downstream secondary flow field and on the aerodynamic performances of the profiles.

Data allows to evaluate the influence of the cited parameters on the radial discharge angle distribution produced by secondary flows.

Typical result are:

• kinetic energy loss contours;

• secondary velocities vectors distribution;

• influence of an incidence angle variation on the flow field produced by the turbine passage.

Off design condition can lead to a great variation in the radial discharge angle distribution, with peak values in the “overturning region” (located close to the endwall) and minimum values in the “underturning region” (located between the endwall and the blade mid-span).