Phase-locked Particle Image Velocimetry investigations were performed to investigate the flow field inside a low-pressure turbine cascade operating at engine-relevant high-speed and low-Re conditions. An application of phase-locked measurements was motivated by the disturb-ance of the flow field by periodically by incoming wakes. The effect of these wakes on the flow field itself and, in particular, on the exit flow angle was of interest for the work presented here. These wakes, which simulate the interaction of an upstream rotor row with the steady cascade in the wind tunnel, were produced by moving cylindrical bars passing upstream the steady cascade with a frequency of 500 Hz. The results quantify the production of turbulence intensity down-stream of the bars and its convection through a blade-to-blade plane at mid-span and in the regime of secondary flow close to an endwall. On time average, less underturning of the cascade was measured under unsteady conditions compared to steady inflow, especially in the secondary flow regime. An unavoidable blade passage phenomenon - the negative-jet effect – was extracted from the measurements. Finally, the results correlate well with comprehensive post-test numerical simulations.    «

Phase-locked Particle Image Velocimetry investigations were performed to investigate the flow field inside a low-pressure turbine cascade operating at engine-relevant high-speed and low-Re conditions. An application of phase-locked measurements was motivated by the disturb-ance of the flow field by periodically by incoming wakes. The effect of these wakes on the flow field itself and, in particular, on the exit flow angle was of interest for the work presented here. These wakes, which simulate t...    »