Evolution of Thermal Fields on a Streamlined Surface Heated by a Shock Wave and Plasma of a Pulsed Surface Discharge

An experimental study was conducted to investigate the thermal fields in the boundary layer along the wall of a gas-dynamic channel near a rectangular insert. The study focused on conditions following the passage of a shock wave and during the initiation of a pulsed surface discharge in the flow. The heating and cooling dynamics of the region affected by the pulsed sliding discharge along the dielectric surface in the flow separation zone were examined. Registration of the radiation of the channel walls in the range of 1.5–5.1 µm was carried out through the side windows of the test (discharge) chamber of the shock tube, transparent both for the thermal radiation of the walls and for the visible radiation of the discharge. It is shown that the cooling of the insert region, heated by a localized nanosecond discharge in the leeward zone, occurs in less than a millisecond; on the shock-heated surface of the channel in the windward zone of the insert, cooling occurs in several milliseconds. The study measured radiative, conductive and convective components of heat fluxes in various supersonic flow configurations. The experiments were conducted in the range of shock wave Mach numbers \({{{\text{M}}}_{0}} = 2{-} 4\) and high-speed flows behind them, respectively, with Mach numbers \({\text{M}} = 1.1{-} 1.4\).