High order direct numerical simulation of compressor cascade channel separated flow

Separated flow of V103 compressor cascade was numerically simulated by directly solving the two-dimensional Navier-Stokes equations using high order finite difference schemes. The numerical results showed that in the transient flowfield, there existed an obviously separated flow at the rear of the suction side with a large-scale separated vortex followed by alternative second vortex and shedding-vortex forming the wake. In the time-averaged flowfield, a short separated bubble was formed and identified by the pressure platform of the pressure distribution on the suction side of the blade. Compared with two-dimensional flat separated flow, both the transient and time-averaged flowfields were similar with the same vortex structure. However, the non-dimensional vortex-shedding frequency of cascade was twice times of the flat flow. The time-averaged pressure distribution on the blade surfaces coincided with the numerical results in the references except the separation area. Compared with the reference results, the present separated flow axial length was 41% bigger than the former. At last, second order statistics of pulse velocity in the separation area were bigger than those in the wake, indicating the unsteadiness of the separated flow. © 2020, Editorial Department of Journal of Aerospace Power. All right reserved.