Interaction of wake disturbance with compressible transitional boundary layers in a low-pressure turbine cascade under rotor-stator interaction

Abstract Transition-process-resolving numerical simulations of compressible transitional flows subjected to rotor-stator interaction in a low-pressure turbine cascade were performed. Cases of small and large Strouhal numbers ( St ) of blade passage, and with and without isotropic free-stream turbulence (IFST) are compared. Cascade geometry is T106, and the computations are conducted at its design point condition. A higher-order finite difference method based on sixth-order compact difference and tenth-order filtering is employed. Variation in St and the intensity of IFST changes the frequency of turbulence inflow, the convection and propagation of turbulence, and the interaction of disturbance with boundary layers in the blade passage. The changes result in different pressure fluctuation in the passage. Because pressure fluctuation can convey information away from the passage, it is expected to be used for diagnosing boundary layer states around the blade indirectly away from the passage.