Steady and unsteady numerical investigation of transitional shock-boundary-layer-interactions on a fan blade

The present numerical study was performed to investigate the impact of both the Reynolds number variation and the used turbulence model to capture the boundary layer development on the characteristic of a BR710 fan blade. A one-equation model of Spalart Allmaras with an optional semi-empirical transition model of Abu-Ghanam Shaw has been applied. The transition model allows the boundary layer development from a laminar to a turbulent behaviour to be taken into account. This is of particular importance at low Reynolds numbers and thus high operating altitudes of airplanes when the transition location moves further downstream to the trailing edge. Therefore the interaction between the shock waves of the transonic fan blade row and the boundary layer leads to a significant change of the characteristic. The steady numerical studies of the 3-D blade passage have been carried out with the commercial 3-D Navier–Stokes solver NUMECA. Additionally an unsteady calculation has been applied to explain the penalty in efficiency on high operating altitudes.