Active electrode isolation for advanced plasma actuators

The current document describes a novel concept for actively isolating neighboring electrodes of multi-electrodes plasma actuators. For these actuators, such as the phased-array actuators (Corke and Matlis 2000) or the oscillating-wall ones (Choi et al. 2011), at different time instants, different sets of electrodes are operated; meanwhile the not-operated electrodes are floating grounds for the circuit. The proposed concept consists of splitting the amplitude of the voltage signals supplied to the operated electrodes and needed to generate the plasma discharge in a baseline signal and a time-modulated component. While the first is to be continuously supplied to all electrode sets and is of amplitude below the breakdown voltage for the considered fluid and plasma actuator, the latter, supplied only to the operated electrodes, has an amplitude such that, when superimposed to the baseline voltage, leads to the plasma discharge. The proposed operation reduces the voltage difference between operated and not-operated neighboring electrodes. Therefore, related detrimental interactions, such as parasitic discharges, are prevented. Two proof-of-concept experiments are performed and presented showing the proposed operation mode effective and efficient.