schlierenvisualisering
Schlierenvisualisering, often simply referred to as schlieren, is an optical technique used to visualize flow patterns in transparent media, such as air or liquids, that are not ordinarily visible to the naked eye. It works by detecting variations in the refractive index of the medium. These variations are typically caused by differences in density, temperature, or pressure. The fundamental principle relies on the fact that light bends (refracts) as it passes through regions with different refractive indices.
A basic schlieren setup involves a light source, a focusing element (often a spherical mirror or lens),
When the deflected light rays hit the knife-edge, some will be blocked, while others will pass. This