Numerical investigation on controlling separated cascade flows by using jets

Separated flow is studied on a 2D cascade using steady and unsteady jets. The time-mean jeted flow rates are not more than 1% of the inlet mass flow rate. The results show that, by means of adding jets on the suction surface, the separated flow could be effectively controlled and the time-mean performance of flow field could be remarkably improved. The optimal jet direction varies with each type of jets. The most effective jet location is at a distance upstream of the time-mean separation point which distinguishes from that of unsteady jet. For a fixed slot width, the effectiveness of injection associates with the balance between injection velocity, or jeted flow rate, and blockage. There is an optimal frequency for the unsteady jet.