Calculation of Unsteady Wake/Rotor Interaction

This paper presents a numerical analysis of wake/rotor interaction using a time-marching solution of the unsteady, nonlinear Euler equations. The incoming wakes are specified through the unsteady inflow boundary conditions. The lagged periodic boundary condition that arises due to unequal rotor/stator pitches is handled by a new technique that inclines the computational plane in time. Comparison of results for a flat-plate cascade with results using a linear analytic theory demonstrates the method's capability to accurately predict unsteady forces, moments, and radiated sound. Results are also presented for a low-speed turbine.