Time-correlated force production measurements of the dielectric barrier discharge plasma aerodynamic actuator

An atmospheric-pressure dielectric barrier discharge (DBD) plasma, operated as a surface-mode discharge with a single encapsulated electrode and an asymmetric electrode alignment, is known to couple momentum into the surrounding neutral fluid and through this coupling has shown considerable promise as an aerodynamic flow control device. Several different models, often with conflicting explanations, have been offered to explain the process of this momentum coupling. The DBD is known to proceed in two stages during the discharge cycle, one on the positive-going portion of the applied ac high-voltage waveform and the other on the negative-going portion. By using the actuator to drive a second-order mechanical system, we show here that the great majority (97%) of the momentum coupling occurs during the negative-going portion of the discharge cycle and we relate this behavior to dramatic differences in the structure of the discharge revealed with high-speed photography. This information is critical in evaluating descriptions of the momentum-coupling processes in the plasma.