Optimisation of multiple encapsulated electrode plasma actuator

The standard dielectric barrier discharge plasma actuator, in which an asymmetric arrangement of electrodes leads to momentum coupling into the surrounding air, has already demonstrated its capability for flow control. The new design of such an actuator exploits the multi-encapsulated electrodes to produce higher velocities providing more momentum into the background air. As the number of encapsulated electrodes increases and other variables such as the driving frequency and voltage amplitude are considered, finding the optimum actuator configuration for increasing the induced velocity becomes a challenge. Specially the task is prohibitive if it is implemented on an ad hoc basis. This paper uses D-optimal design to identify a handful of experiments, for which the velocity is obtained by Particle Imaging Velocimetry measurement. Afterwards, the velocity is modelled through a surrogate modelling practice, and the model is validated both experimentally and statistically. To find the optimum actuator configuration, numerical optimisation is conducted and the results are investigated through experiment. The results show that the surrogate modelling approach provides a cheap and yet efficient method for systematically investigating the effect of different parameters on the performance of the plasma actuator.