Flow control- manipulation of flow behavior have received significant research attention since the beginning of boundary layer theory, due to the notable drawbacks of unplanned flow separation: acoustic noise problems, drag increase, lift losses, instabilities, etc. Flow control methods can be classified by their technology and their form of flow perturbation. One of these technologies is plasma actuation: impulsively perturbing the flow via plasma with no moving parts, low actuator mass and fast time response.
A cathodic arc is a subset of electric arcs that results in electron emission and vaporization of cathode material. The Cathodic Arc Actuator (CAA) is a device that generates cathodic arc jets. Due to its coaxial structure, the particles are accelerated in the direction of the symmetry axis- instead of the direction between electrodes. Although this technology has largely been utilized for propulsion and material processing, it can also be applied to flow actuation and control. For the purpose of flow control the direction of the plasma generation creates a unique method of inserting perturbations perpendicular to the flow.
In this study, the CAA was applied to a canonical separated flow, the backward facing step. The influence of the CAA on the flow, along with detailed processing of the electrical measurements for the purpose of characterizing the efficiency of the devise will be presented.