Pulse volume discharge behind shock wave in channel flow with obstacle

Abstract

Action of the localized pulse energy input on the supersonic channel flow around and downstream the obstacle was studied. The pulsed volume discharge with preionization via two plasma sheets was initiated in a non-stationary gas-dynamic flow in the channel with an obstacle (ledge). Experiments were in the shock tube 24mm×48mm with a special discharge chamber. The initial plane shock wave M=2.8–3.4 with a uniform flow behind it passed over the ledge in the form of a parallelepiped of 48mm×6.2mm×2mm, placed on the lower wall of the discharge chamber. The discharge was initiated in different moments of a plane shock wave (and gas flow behind it) movement in the channel. The discharge electric current duration was 200−−500ns. High-speed shadow videos of shock waves from discharge localization zones were recorded. The comparison of shadow flow images, the discharge instant glow images and CFD flowfields were matched. The pulse volume discharge energy was redistributed in the inhomogeneous flowfield (plasma self-localization effect). Influence of the localized pulse energy input on the channel supersonic flow was analyzed: dynamics of shock (blast) waves produced by self-localized plasma in separation areas near the ledge and also discontinuities produces as a result of discontinuities breakdown at oblique shock area ionization. Initial flow configuration disturbed by the pulse volume discharge was restored in time interval up to 120μs.