In recent years, revolutionary technologies of inlet design were developed in response to environmental concerns such as reduction of noise and pollution. Part of these efforts are directed towards reduction of overall weight and drag of air vehicles. BLI (boundary layer ingesting) serpentine integrated inlets, with high curvature are a critical component of this design trend and very attractive for weight and drag reduction. However, they suffer of the disadvantage of thick boundary layer ingested into the inlet coupled with S–shaped offset that induce losses of total pressure and flow uniformity inside the inlet.
The current study displays control authority over flow non-uniformity using several active flow control methods, such as suction and blowing. The analysis is performed using RANS and URANS simulations. The focus is on applying active flow–control method on a BLI inlet in order to restructure the flow inside the inlet and to improve engine fan–face distortion levels. First, a baseline case, without any flow control was calculated and compared to previously published experimental and computational results. The results of the baseline calculation were used to determine the flow mechanisms that characterize the formation of flow distortion inside the inlet. Based on these results, desirable positions of suction slots could be determined in various combinations. However, to achieve significant decrease in flow distortion, non-neglectable mass flow was required for the suction. Therefore, combinations of steady suction and steady/oscillatory blowing were examined. Using this AFC approach, a significant improvement in pressure recovery and flow uniformity was demonstrated, at a negligible loss in the mass flow rate.
