Experiments to stabilize an unsteady Mach 3 shock wave on a truncated body fitted with a central spike have been conducted in the ONERA RICh blowdown wind tunnel. Stabilization was achieved by means of a negative corona discharge created at the tip of the spike. Several runs have been performed, with a freestream unit Reynolds number varying in the range of [0.9x10E7-3.5x10E7 m(exp-1)]. Onboard discharges can be generated using an ac or dc potential between the tip of the spike and the truncated face, similar to the setup of Kuo (Kuo, S., Kalkhoran, I., Bivolaru, D., and Orlick, L., Physics of Plasmas, Vol. 7, No. 5,2000, pp. 1345-1348.). Without discharge, for a certain spike length the authors observe that, depending on the Reynolds number or the surface state of the spike, the shock front is unsteady or not. In the case of a naturally unsteady shock front, we observe a complete stabilization of the shock when a negative discharge is generated at the spike tip. With positive discharges, the effect is weaker. Both discharges are pulsed, and their input power is less than 1 W. Discharge imaging and current measurements indicate that the negative discharge is a Trichel-pulsed corona discharge, whereas the positive discharge is a streamer discharge. An order-of-magnitude analysis and infrared imaging indicate that continuous volume and surface heating are negligible. To explain the stabilization mechanism, the authors argue that the pulsed discharge acts as an acoustic source tripping the boundary layer, thus leading to a bypass transition to turbulence.
Mach 3 shock wave unsteadiness alleviation using a negative corona discharge
Untersuchung der Schockwellen-Unstetigkeitsminderung bei Mach-3 mit Hilfe einer negative Koronaentladung
AIAA Journal ; 46 , 8 ; 2042-2049
2008
8 Seiten, 15 Bilder, 21 Quellen
Article (Journal)
English
Mach 3 Shock Wave Unsteadiness Alleviation Using a Negative Corona Discharge
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