Large-Eddy Simulation of Transitional Flow Through a Low-Pressure Turbine Cascade

Subsonic, transitional flow through a low-pressure turbine (LPT) cascade is investigated using high-order compact difference scheme in conjunction with large-eddy simulation (LES). Three-dimensional simulations are performed at chord inlet Reynolds numbers (Re) of 25,000 and 50,000. The inlet Mach number is approximately 0.06. An MPI-based higher-order accurate, Chimera version of the FDL3DI flow solver developed by the Air Force Research Laboratory at Wright Patterson Air Force base, is extended for the present turbomachinery application. The implicit solver is based on an approximate factored time-integration method of Beam and Warming. Fourth-order compact-difference formulations are used for discretizing spatial derivatives in conjunction with sixth-order non-dispersive filtering. Solutions are obtained both with and without a sub-grid scale (SGS) model. A dual topology, 16-block, structured grid generated using GridPro is utilized for all simulations. The flow features are examined, and the results for both LES approaches are compared to each other, and with experimental data.