Prandtl–Glauert singularity

Scheme of the phenomenon

F/A-18 showing the effect of singularity

The Prandtl-Glauert singularity is a point at which a sudden drop in air pressure occurs and is generally considered to be the cause of the visible condensation cloud that appears when an aircraft passes through the sound barrier (although there is still controversy about its cause^{[citation needed]}). This is an example of a mathematical singularity in aerodynamics.

If the air humidity is sufficient, when an object reaches the speed of sound an extreme pressure variation is produced, which can cause the condensation of water vapor present in the air.

Effect of the singularity seen in Operation Crossroads' BAKER test