A beautiful reminder that physics is everywhere, even in soapS

You're looking at a figure from a paper titled "Visualization of flow patterns past various objects in two-dimensional flow using soap film," published in the latest issue of Physics of Fluids. ([Very] hi-res version available here.) The authors write:

Although many advanced experimental flow visualizations, such as particle image velocimetry or laser Doppler velocimetry, have been developed and used in fluid dynamics research, the use of flowing soap films has remained as an educational tool and economical visualization technique to study fluid-structure interaction and hydrodynamic instability in two-dimensional fluid flows.

Making use of the optical properties of the soap film and high-speed photography, the wake evolution and vortex patterns behind different bodies can be tracked and captured.

I'll be honest, I have a pretty limited understanding (ie none whatsoever) of what's giving rise to these interference patterns, let alone what these fluid structures are called (according to FYFD, highlights in this set of images include "wakes behind bluff bodies, interacting cylinders, and flapping flags"), but wow — talk about stunning.

Physics of Fluids via Fuck Yeah Fluid Dynamics