On The Use of Supersonic Jet-Curtains for Control of Moments on Tailless Aircraft

The purpose of this study was to explore the replacement of conventional moving control surfaces on a typical tailless aircraft model at high subsonic cruise speeds. Since the efficacy of sweeping jet actuators was only demonstrated at low speeds, the current test considered their potential replacement by Supersonic Steady Jets (SSJs) of identical nozzle dimensions. It was shown that even a single SSJ properly located and appropriately oriented may outperform an array of actuators whose location and orientation did not take into consideration the changing local flow conditions. The test article chosen was the SWIFT model that represents a typical blended wing-body configuration of a tailless aircraft. It was selected because it was tested extensively using Sweeping Jet Actuators (SJAs) that could be used for comparison. When a single supersonic jet designed for Mn=1.5 was used to control the pitch it was able to increase the trimmed lift almost as well as an array of SJAs while providing a much better yaw control at small accompanying rolling moment. These tests proved that the momentum input is but one of many parameters controlling the flow and they demonstrated the richness of the parameter space involved in AFC design even after the wing design was frozen