The Double Knife-Edge Technique for Improved Schlieren Sensitivity in Low-Density Hypersonic Aerodynamic Testing

William A. Stolzenburg

The double knife-edge modification of the classical “Z”-type Toepler schlieren system to provide a symmetrical double knife-edge cutoff at the schlieren image is illustrated and described. Experimental results of the use of this improved diagnostic technique for the visualization of low-density hypersonic flow field schlieren are included. Single and double knife-edge schlieren photographs made with the same schlieren system at similar low-density hypersonic flow field conditions are compared and the advantages and disadvantages of both techniques are discussed. The relationship of light-source image size to double knife-edge separation and its effect on schlieren photograph exposure quality are also illustrated and discussed.

Print ISSN
Published
1965-08
Content type
Original Research
DOI
10.5594/J06018