Hot-Wire Investigation of Turbulent Flow over Vibrating Low-Pressure Turbine Blade Cascade

This paper presents experimental results on unsteady turbulent flow in a low-pressure turbine blade cascade, specifically exploring the effects of blade vibrations on wake topology and turbulence structure. The study focused on comparing the flow patterns of a stationary blade to those observed during its bending and torsion vibrations. Hot-wire anemometry was used for the experimental analysis. The flow velocity was characterized by a chord-based Reynolds number of approximately Rec≈2.3×105, with the excitation frequency set at f=72.8Hz. The findings reveal a strong effect of the bending mode on the wake topology, resulting in a 5% reduction in the streamwise velocity deficit compared to the stationary and torsional modes. Additionally, the bending mode encourages the active formation of large vortices in the wake region, which leads to a fivefold increase in the integral length scale. In contrast, the Kolmogorov microscale remains consistent across all scenarios, exhibiting a minimum in the wake region and a maximum in the inter-blade space. The paper also discusses the impact of blade oscillations on the energy dissipation rate. Various calculation methods yield consistent results, indicating that the lowest dissipation rate occurs during the bending mode. Furthermore, the paper emphasizes the spectral analysis of turbulent flow and provides a comprehensive assessment of the Taylor microscale under different experimental censorious.