A high-speed schlieren system in a Toepler-Z configuration is used for flow visualization for a transonic flow field around a supercritical airfoil. Schlieren pictures have been recorded mainly at a framerate of 16 kfps. From the set of images streak records can be generated. These streak records offer further possibilities of flow analysis like the determination of shock or pressure wave frequencies. The schlieren setup has been extended to a quantitative schlieren setup using a weak plano-convex lens in the setup as a “calibration lens”. This lens allows a quantitative relationship between the image pixel intensity and the refraction angle. The quantitative schlieren technique offers the possibility to determine the density gradient as well as the flow density far away from the airfoil.

Date Published: 28 January 2019
PDF: 6 pages
Proc. SPIE 11051, 32nd International Congress on High-Speed Imaging and Photonics, 110510L (28 January 2019); doi: 10.1117/12.2524708

Published in SPIE Proceedings Vol. 11051:
32nd International Congress on High-Speed Imaging and Photonics
Michel Versluis; Eleanor Stride, Editor(s)