ON THE MODAL ANALYSIS OF FAST RESPONSE AERODYNAMIC PRESSURE PROBE DATA

This paper presents the analysis procedure adopted to study the unsteady aerodynamic measurement data obtained from a Fast Response Aerodynamic Pressure Probe (FRAPP) downstream of a low pressure turbine (LPT) rotor in a 1.5-stage turbine test rig. The method, which is based on the acoustic theory of Tyler and Sofrin, focuses on the investigation of the main structures constituting the unsteady flow field. In the last section of this paper, an example of applying the mentioned technique onto experimental data obtained in a subsonic turbine test facility is shown. The interactions between the stator and rotor wakes, secondary flows and the turbine exit guide vanes (TEGVs) potential effect are identified, and their importance in the assessment of the aerodynamic and aeroelastic performance of modern low pressure turbines is analysed.