Retroreflective shadowgraph technique for large-scale flow visualization

A simple and robust retroreflective shadowgraph technique is presented for the visualization of refractive phenomena across a broad range of scales in space and time. Originally developed by Edgerton, it is improved here with techniques for producing coincident shadowgram illumination. The optical components required to construct a simple system are discussed, including the retroreflective screen material. The optical sensitivity of the system is explored for visualization of shock waves and turbulent eddies. The shadowgraph system is used here to visualize experiments performed in the laboratory, on a military test range, and in an open field. (C) 2009 Optical Society of America