Optimizing electrode arrangement in plasma actuators: a study on induced velocity and efficiency

Abstract

This study investigates the performance of two types of multi-encapsulated electrode (MEE) plasma actuators, compared to a typical dielectric barrier discharge (DBD) plasma, in quiescent air. Our objective is to determine whether the multiple encapsulated structures can enhance the performance of the plasma actuator. We analyse the flow field using particle image velocimetry (PIV) and schlieren visualisation and calculate the distribution of body force over the gas volume based on the Navier–Stokes equations from velocity measurements. Our findings demonstrate that the starting vortex behaviour is influenced by electrode arrangement. Specifically, we observe that when the first encapsulated electrode is positioned closer to the exposed electrode, then a significantly higher induced velocity can be obtained compared to the baseline condition. In fact, the induced velocity can be increased by up to 1.5 times under this optimise configuration. These results highlight the importance of electrode arrangement in the plasma actuator design. Based on our body force estimation, we find that MEE plasma actuators exhibite a significantly higher momentum transfer, particularly in the wall normal direction. Our investigation on the mechanical efficiency also reveals that the optimised configuration proposed in the present study can significantly enhance the efficiency. In fact, we observe a four-fold increase in maximum efficiency compared to the typical configuration. These results suggest that the proposed configuration could be a promising solution for improving the mechanical efficiency of plasma actuators.