Crowds and water have more in common than you’d think - they both flow like a fluid, with predictable patterns that can turn perilous if not properly managed. Looks like the physics of human herds is no bull, as researchers have uncovered the fluid dynamics behind dangerous crowd crushes.
Is this not a solved problem?
No. Fluid dynamics is very complicated. It seems like crowds are much simpler, although so far their only advice is to avoid walls, etc.
https://arstechnica.com/science/2018/10/turbulence-the-oldest-unsolved-problem-in-physics/