Abstract: Shock waves in supersonic flows can be effectively controlled by gas
discharge plasmas, and thermal mechanism has gained preliminary consensus in
the literature. In the present paper, we try to validate the thermal mechanism
of shock wave control by gas discharge plasmas experimentally. Surface
dielectric barrier discharge (DBD) plasma and surface arc discharge plasma were
selected as representatives of low-temperature cold plasmas with weak thermal
effect and low-temperature thermal plasmas with strong thermal effect,
respectively. An oblique shock wave from a wedge was controlled by these two
types of gas discharge plasmas respectively in a Mach 2.2 wind tunnel.
Schlieren photography and gas pressure measurement results demonstrated that
the cold DBD plasma had no obvious control effect on the shock wave, but the
shock wave structure was distinctly changed by the hot arc discharge plasma.
Under test condition of arc discharge power 1.3 kW, the start point of shock
wave shifted upstream 4 mm, the shock wave angle decreased 8.6% and its
strength weakened 8.8%. Therefore, we conclude that only the low-temperature
thermal plasmas with substantial heat energy addition to the supersonic flow
field have the control abilities on shock wave. This work will provide more
evidence on the thermal mechanism of shock wave control by gas discharge
plasmas.
