Demonstration of the applicability of a Background Oriented Schlieren (BOS) method

Background-oriented schlieren (BOS) techniques

“…The application illustrated in the patent application is the diamond-like pattern of a supersonic free jet, which had been recorded by H. Richard. It is also one of the applications described in a conference paper by Richard et al (2000), which was presented in Lisbon in July 2000. Also described herein is the experimental and computational effort required for subsequent quantitative determination of density.…”

“…However, any non-twodimensionality in the flow field will distort the results, since the BOS method is a line-of-sight integrating technique. A first step toward the determination of the density distribution by computation of the Poisson equation for BOS data of two-dimensional transonic flows has been presented by Richard et al (2000) and Richard and Raffel (2001). However, a more complete analysis by tomographic algorithms is required in order to deal with three-dimensional density fields.…”

Qualitative investigation of a propeller slipstream with Background Oriented Schlieren

“…Schlieren (BOS) method is particularly useful for the investigation of flow structures with local density variations as present in the wakes of propeller blade tip vortices (Richard et al, 2000 andKlinge et al, 2006). The BOS method is relatively easy to set-up (Dalziel et al, 2000) and it is possible to extract 2D quantitative data from 3D flows (Venkatakrishnan et al, 2004).…”

“…the Gladstone-Dale relation, Richard et al, 2000). Basically changes in density affect the optical path via the refractive index.…”

Quantitative Measurements of Three-Dimensional Density Fields Using the Background Oriented Schlieren Technique

“…A comparison of this method with holographic filters can be found in the paper of Augenstein et al [1]. Its applicability to different flow problems and even full scale testing was demonstrated by Richard et al [13]. Nafz et al [10] applied BOS to measure the density of a transonic airflow around a turbine blade in a wind tunnel.…”