Schlieren Systems

In the study of supersonic flow, shock and expansion waves are used to determine Mach number. In most situations, however, they are virtually invisible to the naked eye. Fortunately, a system developed in 1864 by German Physicist August Toepler allows waves to be viewed clearly for accurate angular measurements.

Schlieren (plural for the German word “schliere”) are optical inhomogeneities in transparent materials.  In supersonic flow, air experiences very large changes in density as it approaches, passes through and trails shock waves.  As the density of air changes, so does its index of refraction.  Changes in index of refraction essentially turn the shock waves into lenses, bending the light.  Toepler’s Schlieren “system” separates the light bent by the shock waves from the background light, allowing the shocks to be viewed as a combination of bright and dark areas.

Individually crafted, AEROLAB offers Schlieren Systems for any application: supersonic wind tunnels, transonic wind tunnels, supersonic nozzle study, etc.

Common Applications:

Transonic and supersonic flow visualization

AEROLAB Schlieren Systems employ a conventional double mirror system with the light source and knife edge offset from the axis of the mirrors. Considerable flexibility is achieved by mounting components on separate, adjustable stands. The mirrors are parabolic first-surface mirrors of telescope quality correct to within 1/4 wave length, aluminized and over coated.


  • Light source - all-in-one solid state power supply and short-arc xenon lamp with lens, track-mounted adjustable aperature (100-250 VAC 50/60 Hz)
  • Two telescope-quality parabolic mirrors - frame mounted with fine adjustment knobs
  • Knife edge - adjustable in all three axis and angle of inclination with fine adjustment knobs
  • Plain mirror - first-surface to reflect the image to a convenient viewing location
  • Viewing screen

Standard mirror sizes:

  • 6-inch mirrors and 48-inch focal length
  • 8-inch mirrors and 64-inch focal length
  • 10-inch mirrors and 80-inch focal length
  • 12.5-inch mirrors and 100-inch focal length

  • Custom Sizes