Abstract

Dielectric-barrier-discharge (DBD) plasma actuators are unique. They are all electric devices without moving parts (i.e. no valves, diaphragms, cylinders or gears). DBD plasma actuators are therefore light and fast-responding, which can be easily integrated into air and land vehicles for flow control. One of recent developments in DBD plasma actuators is to use them as virtual actuators for flow separation control, replacing control surfaces of aircraft, such as vortex generators, flaps and slats. For example, drag penalty associated with mechanical vortex generators can be avoided by using DBD plasma vortex generators on demand, i.e. only when they are required during take-off and landing. Virtual Gurney flaps based on DBD plasma actuators can be attached at the trailing edge of an aerofoil. Plasma-wall jet issued against the flow creates a local stagnation region with high pressure on the pressure surface, enhancing lift when virtual Gurney flaps are activated. Virtual plasma slats can be configured using symmetric DBD plasma actuators. Spanwise vortices are created when the wall-normal plasma jet is issued against the freestream, helping prevent leading-edge flow separation to give a stall delay at high angles of attack. Recent developments of these and some other plasma actuators will be discussed in the context of drag reduction and flow control.