Numerical study of wake effects on the boundary layer of a high lift turbine cascade at several strouhal numbers and flow coefficients

In this study, the flow through the MTU-T160 low pressure turbine cascade is computed in a set of steady and unsteady RANS simulations involving wake impingment. Two characteristic variables, the Strouhal number Sr as well as the flow coefficient φ are modified while keeping the Reynolds number and Mach number fixed. It is observed that increasing Sr leads to lower total pressure loss of the cascade for φ ≤ 1 and higher total pressure loss for φ > 1 while increasing φ generally leads to larger losses. While reducing the size of the separation bubble, increased values of φ also produce more turbulence friction losses upstream of the separation and downstream of the reattachment of the flow compared to lower flow coefficients. Steady state simulations with mixing plane interface show significantly different results compared to unsteady time-mean simulations in terms of qualitative and quantitative loss change with variation of Sr and φ.