Large-eddy simulation of plasma-based turbulent boundary-layer separation control

Large-eddy simulations were carried out in order to numerically describe plasma-based control of turbulent boundary-layer separation. The configuration consisted of a flat-plate section, over which the boundary layer developed, followed by a curved convex rearward-facing ramp, corresponding to an experimental arrangement. A single dielectric-barrier-discharge plasma actuator was then employed to reduce the extent of the separated flow region. Solutions were obtained to the Navier--Stokes equations, which were augmented by source terms used to represent plasma-induced body forces imparted by the actuator on the fluid. A simple phenomenological model provided the electric field generated by the plasma, resulting in the body forces. The numerical method used a high- fidelity time-implicit scheme, employing domain decomposition in order to perform calculations on a parallel computing platform. Simulations were first conducted for an isolated actuator, which were used to optimize parameters inherent in the plasma model. Subsequent calculations were then carried out for the plate development section and for the plate/ramp combination, using both continuous and pulsed control. All simulations were compared with experimental measurements, which indicated that, although some deficiencies were apparent in the plasma model, they appeared to be adequate for use with large-eddy simulation in the exploration of plasma-based control for turbulent wall-bounded flows. DOI: 10.2514/1.J050014