QUANTITATIVE 3D DENSITY MEASURMENT OF SUPERSONIC FLOW BY COLORED GRID BACKGROUND ORIENTED SCHLIEREN (CGBOS) TECHNIQUE

摘要

The background oriented schlieren (BOS) technique is one of the visualization techniques that enable the quantitative measurement of density information in the flow field with very simple experimental setup. The principle of BOS is similar to conventional Schlieren technique, it exploit the bending of light caused by refractive index change corresponding to density change in the medium and both techniques are sensible to density gradient. In this report we propose the Colored Grid Background Oriented Schlieren (CGBOS) technique. The experiments were carried out in the 0.6 m x 0.6 m test section of supersonic wind tunnel at JAXA-ISAS. A colored grid pattern was used as background image and density gradient in vertical and horizontal direction was obtained. Computed tomographic reconstruction of 3D density information of supersonic flow field around asymmetric body from multi-directional CGBOS images is examined.