The spatial structure of a supersonic flow with an oblique shock wave is studied experimentally during nanosecond surface sliding discharge initiation in a discharge chamber of a shock tube. An inclined shock wave was generated in a supersonic flow around a small obstacle on the lower wall of the channel. A surface sliding discharge was initiated on the upper wall of the discharge chamber directly in the region of interaction of the inclined shock wave with the boundary layer. High-speed shadowgraphy visualization of the flow field was carried out with a frequency of up to 150,000 frames per second at Mach numbers of flows up to 1.70. The discharge characteristics was recorded at different stages of flow and showed dependence on the type of interaction of the oblique shock wave with the boundary layer. It is established that the shock wave dynamics from the discharge depends on the discharge mode and the flow Mach number. According to the digital shadowgraph image processing, the shock waves generated by the discharge affects the shock-wave structure of the flow during ~ 100 μs.

We report investigations of the nanosecond surface sliding discharge in supersonic airflows with the oblique shock wave at Mach numbers of the flow 1.30-1.60 in shock tube. We show that the surface sliding discharge developed in flows as a single channel located near a zone of interaction of the oblique shock with the boundary layer on the wall of the channel. A pulse voltage of 25 kV powered the discharge; the electric current was of 1 kA. The electron concentration in the localized discharge channel was (0.7-1.4).1015 cm-3 and the electron energy was of 1.8-2.2 eV from the analysis the emission spectra. High-speed flow field shadowgraphy after the surface sliding discharge showed that the localized discharge channel generates a strong shock wave, leading to restructuring the shock-wave structure of the flow within ∼100 μs and subsequent relaxation to a stationary configuration.

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