The Marriage of Optical, Tracer and Surface Indicator Techniques in Flow Visualization.

The concept of uniting two or more flow visualization techniques is emphasized. Although this can be done, for a number of flow situations, using instrumentation and methods that have been available for many years, the use of modern technology and intruments makes such unions more easily realized. Some examples of this concept are discussed. Results are presented for a combined optical-shadowgraph and schlieren surface indicator oil flow technique a versatile vapor screen technique using a CW laser and a reversible dye technique. Whether used alone or united to the others the latter is especially valuable for use in a continuous wind tunnel since the surface flow patterns are erasable.