Shock train and pseudo-shock phenomena in internal gas flows

Optical Measurements of Shock Waves in Critical Nozzles at Low Reynolds Numbers

“…Their theory assumes that the p s is the same as the back pressure downstream of the nozzle, i.e., no pressure recovery occurs after the separation. normal shock wave and a boundary layer [9]. The separation pressure ratios for shock trains remain a constant value regardless of the separation Mach numbers.…”

“…The separation pressure ratios for shock trains remain a constant value regardless of the separation Mach numbers. According to a lot of experimental research in the past, a shock train is produced in a confined duct for the free stream Mach numbers beyond around 1.5 [9]. However, the present study shows a shock train appears for the free stream Mach numbers below 1.5 and it may be considered as an effect of the lower Reynolds number, as compared to that of the previous research, in other words, a thinner velocity profile in the boundary layer at the location of the shock.…”

Joule heating flow control methods for high-speed flows

“…144 If the duct is long enough then a mixing region of adverse pressure gradient will follow the shock train, this is shown in figure 57. 145 In the scramjet mode of operation the isolator is also important as the rate of area increase in the combustion chamber is often not large enough to relieve the thermal blockage from the heat addition to a supersonic flow and an adverse pressure gradient occurs. 33 This can lead to boundary layer separation which in turn will result in an oblique shock train forming in the isolator with a supersonic core flow.…”

The effect of backpressure on the transition to subsonic flow in the diffuser of a supersonic air intake

“…It is this change in the total pressure that must provide the diffuser for "insulation" from the effect of the combustion chamber on the flow in the throat of the air intake. A large number of papers have been devoted to experimental, theoretical and numerical investigations of supersonic flows with pseudoshock formation in channels [3][4][5][6][7][8][9][10][11][12]. Most of the research is connected with flows in cylindrical or slightly widening (1-4º) channels, which are considered as diffusers (insulators) of supersonic air intakes.…”