This thesis documents the experimental study of the aerodynamic performance of transonic
turbine cascades, with particular emphasis on the profile losses generated at design incidence.
The midspan flow was measured for three transonic turbines from two Siemens industrial gas
turbine engines and were compared with the predictions from the
Kacker & Okapuu (1982) loss system. Loss predictions for a fourth turbine were also made.

The loss predictions did not accurately capture trends observed in the
data. Losses for the turbines were underpredicted, particularly those with negative
inlet metal
angles. An alternative correction for Reynolds number effects due
to Aungier (2006) was shown to slightly improve the loss predictions for a rough cascade.
The measured losses also showed a tendency to level off in a plateau at low supersonic Mach
numbers. This is not predicted by the Kacker & Okapuu loss system.