HIGH-FIDELITY SIMULATIONS OF THE FLOW AROUND T106C CASCADE AT LOW REYNOLDS NUMBER: THE EFFECTS OF FREESTREAM TURBULENCE AND STAGGER ANGLE

Flows in low-pressure turbines are highly dependent on the laminar-turbulent transition of the boundary layer and the separation of the laminar boundary layer. This study focuses on the flow around the T106C low-pressure turbine cascade blade for a low Reynolds number 100,000 and a moderately low turbulence intensity 0.8%. For this paper, three direct numerical simulations (DNS) are carried out to understand the discrepancies observed between the simulations and the experimental data. To that end, the effect of freestream turbulence intensity and blade stagger angle are investigated. A first simulation is performed without freestream turbulence, then a second one is performed with a modified stagger angle, and finally a third one is performed with an injection of synthetic turbulence at the inlet plane based on the synthetic eddy method (SEM). The results are compared to experimental data and RANS simulations. These comparisons show that there are still discrepancies between the flow predicted by the DNS and the experimental measurements. A comparison between DNS and RANS simulations highlights some leads to better understand these discrepancies.