Separation Control with Nanosecond Pulse Driven Dielectric Barrier Discharge Plasma Actuators
Journal article preprint
ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
Pagination or Media Count:
The efficacy of dielectric barrier discharge DBD plasmas driven by high voltage approximately 15 kV repetitive nanosecond pulses approximately 100 ns FWHM for flow separation control is investigated experimentally on an airfoil leading edge up to Re1x106 62 ms. Unlike AC-DBDs, the nanosecond pulse driven DBD plasma actuator transfers very little momentum to the neutral air, but generates compression waves similar to localized arc filament plasma actuators. A complex pattern of quasi-planar and spherical compression waves is observed in still air. Measurements suggest that some of these compression waves are generated by discharge filaments that remain fairly reproducible pulse-to-pulse. The device performs as an active trip at high Re pre-stall angles of attack and provides perturbations that generate coherent spanwise vortices at post-stall. These coherent structures entrain freestream momentum thereby reattaching the normally separated flow to the suction surface of the airfoil. Coherent structures are identified at all tested frequencies, but values of Fsubponent c, exponent 4-6 are most effective for control. Such devices which are believed to function through thermal effects could be an alternative to AC-DBD plasmas that rely on momentum addition.
- Fluid Mechanics
- Plasma Physics and Magnetohydrodynamics