Behavior of Gliding Arc Discharge in a Supersonic Flow

The behavior of a gliding arc discharge in a supersonic flow is investigated. The discharge is generated in a device which combined electrodes in a 2-D convergent-divergent (i.e., Laval) nozzle. Experimental observations with a high-speed camera, as well as measurements of the mass flow rate and local pressure, suggest that a gliding arc discharge was successfully generated in the supersonic flow. The arc displacement velocity fluctuated due to the existence of shock waves, and the ignition position of the discharge shifted further away from the throat as the reservoir pressure increased. Numerical calculations of the fluid dynamics in the nozzle qualitatively describe the experimental observations. The observed and modeled shift of the ignition position can be explained as the product of the pressure and the electrode distance being minimized at the position just before the first shock wave is produced, and where the breakdown occurs.