#jet formation

[nocternalrandomness]

USN Blue Angels in the A-4 Skyhawk over the USS Arizona Memorial, Pearl Harbor (1982)

[nocternalrandomness]

USN Training aircraft over the Naval Air Test Center (1983)

[deaglefifty]

[deaglefifty]

[deaglefifty]

[fuckyeahfluiddynamics]

During explosions, solid particles and liquids packed around the explosive charges can form jets, making a blast wave appear more porcupine-like than spherical. The instability mechanisms that cause this behavior are not well-understood, but researchers suspect the jets are formed due to perturbations in the particle bed on the timescale of the initial shock propagation. The presence of these jets can affect the blast wave's subsequent growth as well as the mixing in its wake. The number of jets produced depends on many factors, including particle type, the geometry of the charge, the ratio of explosive to particles, and even whether the particles are wet or dry. Note the very different natures of the explosions in the video when shown side by side. (Video credit: D. Frost et al)