Schlieren photography is a method of photographing airflow utilizing refraction. It can be applied to visualize things like heat off of a flame, the air pressure around a bullet, a plane breaking the sound barrier, and more.
Schlieren photography requires a precise setup of a light, camera, and mirror. In the Spring of 2022, I built a setup to be able to take my own schlieren photographs. Building this setup required working with electronics to make a very small, controllable, and high powered point light source, 3D modeling and printing to build mounts for various components, and a lot of patience dialing in the exact angles of the light/mirror/camera and camera settings. The setup was repeated for my EN.530.327 Introduction to Fluid Mechanics project.
This video walks through the Schlieren setup and shows some captured video of fluid flow.