Pseudo-shock in radial supersonic flow with swirl

The static and dynamic properties of a pseudoshock in a radial supersonic flow with a swirl between parallel plates were experimentally investigated. The length and pressure recovery of the pseudoshock were smaller than those in a straight channel. Pressure recovery decreased with a growth of the swirl. Pressure fluctuation at two different points along the radius was statistically correlated, so that the mechanism of propagation of a pressure fluctuation could be analyzed. There were two main fluctuations with high and low frequencies and propagating in opposite directions. The former was excited by an oscillation of the air column in the exhaust chamber and propagated upstream as a pressure wave, while the latter was due to an oscillation of the first shock and was convected downstream.