Design and characterization of a novel plasma actuator with combined spanwise and vertical effects for turbulent skin-friction drag reduction

A plasma actuator with adjustable jet direction based on the combination of dielectric barrier discharge (DBD) and corona discharge is proposed and characterized for turbulent drag reduction applications. The results show that an oblique jet and corresponding vortex series are formed through the interaction of the vertical jet by corona discharge and the horizontal jet by DBD. By changing the power input of DBD and corona discharge, both the velocity amplitude and the deflection angle of the oblique jet can be adjusted swiftly, and the maximum deflection angle of the coupled jet is 66.74°. The maximum velocity of the coupled jet reaches 1.77 m/s at a total power consumption of 23.09 W. Keeping the corona discharge parameters constant and increasing the DBD voltage, the relative distance of the vortex core decreases monotonically. There exists an optimal power ratio, making the total vortex intensity maximized. The actuator can provide combined spanwise and vertical control in a complex turbulent boundary layer to achieve better drag reduction.