**Author details**

is fixed to 50%, it means that discharge is ignited half of the time. On a parallel plane, this

**Figure 17** shows lift recovery in percentage of a stalled NACA0015 airfoil equipped with spanwise vectorized actuators located in different airfoil positions [66]. Jet 5 is generated by a DBD actuator located in the leading edge. When actuators are continuously operated, lift increments are limited to about 15%. When operated with a duty cycle strategy, lift increments

Plasma actuators can also be used to reduce noise induced by aerodynamic surfaces, especially by landing gears and trailing edges [76–78]. Studies on bluff bodies have demonstrated the ability of DBD actuators to reduce downstream turbulence, leading to the suppression of

Studies carried out in the last decades have demonstrated the possibility to use DBD aerody‐ namic actuators for active flow control purposes. In this last section, main advantages and

**•** Possibility to locate these actuators in different positions on a surface and over existing

**•** Possibility to tune the on/off actuation strategy depending on the particular fluid dynamic

**•** Use of potentially hazardous high voltages and electromagnetic noise generation.

**•** Effectiveness in flow control for Reynolds numbers typically below few hundred thousand. Disadvantages already introduced will be overcome only when a more detailed knowledge of basic interactions between discharge a neutral gas will be achieved. When higher induced speeds will be available, new and more effective flow control strategies will be developed.

actuation strategy leads to lower power consumption.

68 Recent Progress in Some Aircraft Technologies

particular tones or to an overall noise mitigation up to 4 dB.

disadvantages in the use of these plasma devices will be summarized.

**•** Negligible aerodynamic interferences when they are not active.

are close to 50%.

**4. Conclusion**

aerodynamic bodies.

**•** Fast actuation times.

condition.

Cons

**•** Low power consumption.

**•** Induced velocity below 10 m/s.

**•** Low electric into kinetic conversion efficiency.

Pros

Gabriele Neretti

Address all correspondence to: gabriele.neretti@unibo.it

Electrical, Electronic Engineering Department Guglielmo Marconi, University of Bologna, Bologna, Italy
