Snapshots in the (z,r) plane of temperature fluctuations in the flow and of pressure fluctuations outside for (a) L = 15r₀, (b) L = 20r₀, (c) L = 25r₀ and (d) L = 30r₀. The red arrows show the wavefronts of two consecutive upstream-propagating pressure waves for the nozzle-to-plate distances L = 15r₀ and 25r₀. The color scales range from 0 to 780K for temperature, from red to white, and from −2000 to 2000 Pa for pressure, from black to white.