A model for Nanosecond Pulsed Dielectric Barrier Discharge(NSDBD)actuator and its investigation on the mechanisms of separation control over an airfoil

In order to simulate the flow control problem by using Nanosecond Pulsed Dielectric Barrier Discharge(NSDBD),a one-zone inhomogeneous phenomenological model is constructed based on the experimental and theoretical results.The model is coupled with the unsteady Navier-Stokes equations,which can well predict the compression-expansion wave structures and wave speed compared with experimental results and can be applied to the simulation of the flow control by using NSDBD.The model is adopted to investigate the separation control over NACA0015 airfoil using the NSDBD plasma actuator.The separation-control mechanisms are revealed that the spanwise vortices produced by the plasma actuation play the key role.Each plasma actuation can produce a spanwise vortex around the separation point near the leading edge.The spanwise vortices make the separated free-shear layer unstable and shed away,move downstream along the upper wall,control the flow near the wall,and bring outer flow with high kinetic energy into the near wall region to realize the effective separation control over the upper surface of the airfoil.