Schlieren Optical System & Aerodynamic Tests (1958)
1958 · Short film · 18 min
Synopsis
This color educational film is about the Schlieren system. This optical system detects changes within a test area medium (air) and records the changes in the form of an image on a screen. The image is formed by refraction and scattering from what is introduced into the test area, which are areas of varying refractive index. This film was made in 1958. Schlieren (from German; singular "Schliere", meaning "streak") are optical inhomogeneities in transparent material not necessarily visible to the human eye. Schlieren physics developed out of the need to produce high-quality lenses devoid of these inhomogeneities. These inhomogeneities are localized differences in optical path length that cause light deviation. This light deviation can produce localized brightening, darkening, or even color changes in an image, depending on which way the ray deviates. Schlieren flow visualization is based on the deflection of light by a refractive index gradient The index gradient is directly related to flow density gradient. The deflected light is compared to undeflected light at a viewing screen. The undisturbed light is partially blocked by a knife edge. The light that is deflected toward or away from the knife edge produces a shadow pattern depending upon whether it was previously blocked or unblocked. This shadow pattern is a light-intensity representation of the expansions (low density regions) and compressions (high density regions) which characterize the flow. Opening: exterior shot of…
Uploader's description on archive.org
Details
- Running time
- 18 minutes
- Collection
- Ephemeral Films
Subjects on the Internet Archive
- Schlieren Optical System
- Educational Film
- 1958
- Aerodynamical
- Shell Oil
- Stock Footage
- Periscope Film
