Simulations of compressible channel flow with pulsed-dc plasma actuation for drag reduction

ITAC and the University of Notre Dame (UND) have been jointly working to develop a practical drag reduction technology. The team has been motivated by Schoppa and Hussain’s ideas of disrupting the Streak Transient Growth Instability. In work sponsored by NASA and DARPA, the ITAC/UND team is exploring the application of the pulsed-DC plasma actuator and results have shown unprecedented levels of skin friction drag reduction. In fact, the team has observed more than 70% drag reduction in wind tunnel experiments. The new technology is referred to as “SLIPPS” (Smart Longitudinal Instability Prevention via Plasma Surface). Perhaps most significant is the finding that the power savings provided by the device exceed the power input required to operate the actuator. The achievement of drag reduction with net power savings represents a major breakthrough in aerodynamic drag reduction technology. In wind tunnel experiments over a Mach number range from 0.05 to 0.5, the team has observed drag reductions from 2.5 times to 3.0 times the power required by the actuator. To better understand this phenomenon, the authors are performing fully developed compressible channel flow simulations with a model of the behavior of the pulsed-DC actuator. The model for the pulsed-DC actuator exhibits a quasi-steady wall jet response to the pulsed body force, as well as a transient compression wave response to the current flow that has been modeled as a temperature/pressure pulse.