Flight Control Using Wing-Tip Plasma Actuation

摘要

A concept for liftmodification on a conventional aircraft wing for roll control at low angle of attack with dielectricnbarrier discharge plasma actuators is proposed and assessed through computational fluid dynamics simulations andnpreliminary wind-tunnel experiments. The concept consists of placing plasma actuators around the wing tip to addnmomentum in the direction opposite to that of the flow forming the tip vortex. Because of the limited strength ofnexisting plasma actuators, the assessment is carried out for a relatively small two-dimensional wing (NACA 4418)nwith a rounded tip at zero angle of attack and 15 m=s for a Reynolds number in the range of 1:5 u0001 105n.nComputational fluid dynamics simulations show a significant alteration of the vorticity field downstream of thentrailing edge characterized by a more diffused vortex surrounded by zones of negative vorticity induced by thenactuators and, but not necessarily, outboard displacement of the tip vortex. This leads to a reduced downwash thatnresults in a change in lift of up to almost 20%for actuator strength levels that should be achievable in the short termnwith a new generation of dielectric barrier discharge actuators. The actuator placed on the suction side contributesnthemost to the lift increase, with its induced jet blocking the flowaround the wind tip at the origin of the formation ofnthe tip vortex. Wind-tunnel experimental results support the computational fluid dynamics predictions in bothnmagnitude and trend. Furthermore, preliminary computational fluid dynamics simulations are carried out for ansymmetric nonliftingwing (NACA0018), representative of aircraft tail surfaces at zero angle of attack to generate liftnfor pitch and yaw control. Results indicate lift generation that increases and becomes larger than drag at highernactuator strengths. These promising results show a potential for the proposed concept to replace movable flightncontrol surfaces on future aircraft wings and empennages.