Electrohydrodynamic wind generation in planar DBDs: role of electrode symmetry and geometry
This study experimentally and numerically investigates the electrohydrodynamic (EHD) interaction produced by a surface dielectric barrier discharge (SDBD) plasma actuator at atmospheric pressure. The non-thermal dielectric barrier discharge generates ionic wind, which is characterized using a symmetric annular actuator composed of concentric ring and disk electrodes. Unlike conventional linear SDBD actuators that primarily produce tangential airflow, this annular configuration generates a predominantly vertical ionic-wind jet. The effects of electrode diameter D and thickness delta on the induced wind velocity perpendicular to the electrode plane are systematically examined. The experimental results show a maximum wind velocity of 3.42 m s^{-1} for an optimized electrode configuration with D = 32 mm and delta = 0.06 mm. Numerical plasma-fluid simulations support the experimental trends and provide spatial distributions of airflow velocity, electrohydrodynamic volumetric force, electron temperature, and gas pressure in the plasma region. Additional diagnostics based on ozone concentration measurements and Schlieren imaging show that electrodes with larger diameters, particularly 22 and 32 mm, enhance the height and development of the vertical flow, while increasing electrode diameter also promotes ozone production. The results demonstrate an important trade-off between ionic-wind performance and reactive byproduct generation. These findings provide practical guidance for optimizing annular dielectric barrier discharge plasma actuators for active flow control, air purification, ozone-assisted disinfection, and biomedical plasma applications.