Numerical Validation of Characteristic and Linearized Unsteady Boundary Conditions for Non-Integer Blade Ratios in a Non-Linear Navier Stokes Solver

Unsteady single passage methods for turbomachinery applications are becoming a more and more mature method in predicting unsteady blade-to-blade aerodynamics in a more efficient and accurate way compared to multipassage computations with scaled airfoil geometries. The outlined work presents results of a fourier-based method for phase-lagged boundary conditions using a usual conservative approach at the interfaceplane and compares it to a new characteristic treatment as well as a linearized single row approach. The new method provides results of similar accuracy with improved stability of the algorithm and faster convergence times.