Research on large field visualizaiton based on divergent light reflective layout

Larger scale of flow-field visualization is required for larger wind tunnel, larger test model and longer jet flow. Two methods of the large field visualization were proposed which are based on divergent light reflective layout and are named as the reflective focusing schlieren method and the reflective shadow method, respectively. A reflective focusing schlieren device was built in laboratory which improves the source grid and light source. A visualization field with a diameter of about 1.5 m was obtained. The field uniformity and the minimum exposure time under test condition indicate that the reflective focusing schlieren method could be utilized for the large scale wind tunnel and other situations. Also, to realize the large field visualization for the situation with strong vibration, a diffuse reflective shadow visualization device was set up, and a visualization field with a length of about 2.5 m was obtained for a combustion jet flow. Finally, according to the characteristics of the reflective method, the applicability of the method in larger tunnel layout was evaluated, and the results show that the method is completely suitable for the large-scale wind tunnel visualization.