Development of a Compact Focusing Color Schlieren Technique

摘要

This work introduces a new focusing schlieren technique that is capable of adding color-coded directional information to the visualization of density gradients. Other advantages of the technique are that it does not require manual calibration, has a simple design and is sensitive enough to be used in compact experimental setups. While the overall method is closely related to traditional focusing schlieren, the novelty lies in the use of a color-coded source image that replaces the conventional source grid. The technique benefits from a computer-controlled digital background, which is used for both illumination and display of color-coded source images. Beyond a discussion of the method, first experimental visualization results are presented. The impact of color coding, depth of field and relationship to traditional monochrome focusing schlieren methods are illustrated based on examples involving simple flames and shock patterns.