The Prandtl–Glauert Singularity – Jet Plane Shock Collar

Very cool pictures, but a correction:

Although it is understandable to see how it could be naturally assumed a vapor cone (as the singularity is also known)...

This is incorrect. The P-G Singularity is a hypothesized pressure singularity in flow leading to a true sound barrier that couldn’t be passed. It was based on faulty assumptions and doesn’t hold.

The Prandtl–Glauert singularity is a theoretical construct in flow physics, often incorrectly used to explain vapor cones in transonic flows. It is the prediction by the Prandtl–Glauert transformation that infinite pressures would be experienced by an aircraft as it approaches the speed of sound. Because it is invalid to apply the transformation at these speeds, the predicted singularity does not emerge. The incorrect association is related to the early-20th-century misconception of the impenetrability of the sound barrier.

https://en.m.wikipedia.org/wiki/Prandtl–Glauert_singularity