This work presents the study of the single-dielectric barrier discharge aerodynamic plasma actuator. The physics of the plasma discharge was studied through the time-resolved light intensity measurements of the plasma illumination. Plasma characteristics were obtained and analyzed for a range of applied voltage amplitudes and a.c. frequencies.Based on this data, electro-static and lumped-element circuit models were developed. The time-dependent charge distribution was used to provide boundary conditions to the electric eld equation that was used to calculate the actuator body force vector. Numerical ow simulations were performed to study the eectof the plasma body force on the neutral uid. The results agreed well with the experiments.An application of the plasma actuators to the leading-edge separation control on the NACA 0021 airfoil was studied numerically. The results were obtained for a range of angles of attack for uncontrolled ow, steady and unsteady plasma actuation. The aerodynamic stall of the airfoil was studied. Improvement in the airfoil characteristics was observed in numerical simulations at high angles of attack in cases with plasma actuation. The computational results corresponded very well with experimental observations.