Like airplane wings, helicopter blades have tip vortices. In this photo, the air’s humidity was great enough that the acceleration caused by the passing of the blades caused a pressure Keep reading
Tag: Prandlt-Glauert singularity
Supersonic
Moving supersonically–faster than the local speed of sound–can cause some awesome effects. Among these are vapor cones (a.k.a. Prandlt-Glauert singularities), shock waves, and, of course, the sonic boom.