Fluidic Control of Nacelle Inlet Flow in Crosswind

摘要

The inlet flow of an engine nacelle model is investigated experimentally in the presence of cross flow that induces a complex azimuthal separation pattern over the nacelle's inlet windward surface. The evolution of the separation topology and its response to flow control strategies are investigated in a state-of-the-art crosswind wind tunnel. Fluidicalh-oscillating jets are utilized as the flow control elements at various intensities and locations for a range of inlet mass flow rates and cross flow speed conditions. Based on these investigations, control approaches are devised for optimal suppression of azimuthal separation within each of three characteristic ranges of the inlet mass flow rate. It is shown that the fluidic actuation pattern within each inlet flow segment yields significant broadband reduction of the total pressure distortion, as measured by the circumferential distortion index IDC_(max). At cross flow speeds of 30 and 35 knots, IDC_(max). is reduced by about 60 and 50%, respectively, at actuation mass flow rates of less than 0.3% of the maximum inlet mass flow rate. The successful implementation of segment-optimized spatial flow control configurations indicates that dynamic, real-time reconfiguration of the fluidic actuation with varying inlet- and cross flow can yield tuned, optimal control of inlet separation.