Detached-Eddy Simulation of Rotating Stall Inception for a Full-Annulus Transonic Rotor

Full-annulus detached-eddy simulation (DES) is conducted in this paper to investigate stall inception for the axial transonic rotor, NASA rotor 67. A low-diffusion E-CUSP scheme with a third-order MUSCL reconstruction is used to discretize the inviscid fluxes, and second-order central differencing is used for the viscous terms. An implicit line Gauss-Seidel iteration with dual time-stepping method and second-order temporal accuracy is employed for time integration of the spatially filtered unsteady Navier-Stokes equations in a rotating frame, It is observed that the rotating stall is initiated by the local spike flow disturbance, which quickly induces the rotor to stall roughly over two rotor revolutions. The stall cell covering more than six blade tip passages propagates at 48% of rotor speed in the counter-rotor rotation direction. The process of rotating stall is captured by the full-annulus DES, which indicates that the blockage created by the low-energy vortical flow structure pushes the tip leakage flow to the adjacent blade behind the detached sonic boundary. The unsteady Reynolds-averaged Navier-Stokes (URANS) simulation is also performed for comparison. DES predicts the stall inception roughly one rotor revolution earlier than the URANS model. Overall, DES predicts the stall inception more realistically.