A new plasma actuator configuration for improved efficiency: The stair shaped dielectric barrier discharge (SSDBD) actuator

Plasma actuators have shown their ability for different applications within the active flow control and heat transfer fields. These simple devices are inexpensive, present robustness, low weight and are fully electronic. However, they still present some debilities in terms of durability and maximum induced flow velocity. To overcome these issues, during the last years, a few different configurations of dielectric barrier discharge plasma actuators have been proposed but, always making use of dielectric barrier discharge layers of constant thickness. For the first time, the present study herein introduces a new plasma actuator configuration which makes use of a stair shaped dielectric layer, which aims to increase the induced flow velocity and improve the mechanical efficiency without compromising the durability of the device. In this new concept, instead of using a dielectric layer with constant thickness, the thickness of the dielectric layer decreases along the covered electrode width, which leads to an increase of the plasma discharge extension and an increase of the maximum induced flow velocity. Several actuators based on a stair shaped dielectric layer were experimentally tested and compared with the conventional actuators. The results demonstrated that the stair shaped actuators allow to obtain a plasma discharge 20% longer. It was found that by implementing a stair shaped dielectric layer with 7o slope angle, in a 1.92 mm thickness actuator, it is possible to increase the maximum induced flow velocity in about 32% by consuming 36% less power. These results lead to a mechanical efficiency 5 times bigger than the obtained with conventional constant thickness actuators.