Definition
Plain language
The curved shock wave that forms in front of a blunt object plowing through air faster than the speed of sound.
As stated in the literature
A detached shock wave standing ahead of a blunt body in supersonic or hypersonic flow; resolving it without producing negative pressure at the stagnation point is a core difficulty in re-entry CFD, as in the Apollo command module case.
Why it matters: Getting this shock wave right in simulations is essential for designing heat shields that keep a re-entering spacecraft from burning up.
For example, a returning space capsule racing into the atmosphere pushes a curved wall of compressed, superheated air just ahead of its blunt heat shield.
Heard on the show
“Hypersonic flow around a blunt body, a bow shock that standard solvers routinely crash into because they produce negative pressure at the stagnation point and just die.”Episode 042 — An Agentic Scientific Computing System That Actually Remembers What It Learns