Plasma Actuators Optimization Using Stair Shaped Dielectric Layers

Plasma actuators are very simple devices which have been shown to be effective in a wide variety of applications, such as separation control, wake control, aircraft noise reduction, modification of velocity fluctuations and boundary layer control. More recently, it has been also proved their ability for applications within the heat transfer field, such as film cooling of turbine blades or ice accumulation prevention. These simple devices are inexpensive, present robustness, low weight and are fully electronic. Considering the importance of these devices, the improvement of their efficiency is a subject of great interest for worldwide scientific community. It is known that, by reducing the plasma actuator dielectric thickness, the induced flow velocity increases. However, it is also known that, thin plasma actuators present short lifetime and quick dielectric layer degradation. Till now, only actuators with constant dielectric thickness have been studied. In the present work, a new concept of plasma actuator is studied: The stair shaped dielectric barrier discharge plasma actuator. This new device present a dielectric layer which provides a decrease of the dielectric thickness along the covered electrode width. This lead to an extended plasma discharge and an increase of the induced flow velocity and efficiency. In addition, the plasma discharge is weakened on the onset of plasma formation which prevents the quick degradation of the dielectric layer and leads to an increased actuator lifetime.