Phase-resolved Body-force Determination of an AC-DBD Plasma Actuator in Laminar Flow

In continuation of earlier efforts (Kriegseis et al., 2013, JPhysD, Benard et al., 2013, JPhysD, Pereira et al., 2014, JApplPhys, D\"{o}rr\&Kloker, 2015, JPhysD) the present study revolves around the PIV-based characterisation of plasma-induced body-force fields in laminar boundary layers ($U_\infty \leq 30$ m/s). Both common approaches, Navier-Stokes equation (NSE) and vorticity equation (VE), are applied to the obtained phase-resolved velocity data (24 phases). The extracted forces are compared in terms of time-averaged and phase-resolved force distributions. Additional force-magnitude information is determined to evaluate the impact of the airflow on the actuator performance. The plasma actuator exerts a co-flow force (along mean flow) in a flat-plate laminar boundary-layer flow. The power consumption of the actuator was found constant for $U_\infty \leq 30$ m/s. Interestingly, the determined force from NSE changes significantly with increasing airflow velocity, whereas the calculated force from VE budgets a constant integral force magnitude. Consequently, the implied assumptions of either approach are revisited and limits of the formerly consider suitable simplifications -- at least for quiescent air -- are discussed on the basis of the obtained data.