This paper summarizes a variety of optically based flow-visualization techniques used for high-speed research by the Configuration Aerodynamics Wind-Tunnel Test Team of the High-Speed Research Program during its tenure. The work of other national experts is included for completeness. Details of each technique with applications and status in various national wind tunnels are given.Lamar, John E. (Editor)Langley Research CenterFLOW VISUALIZATION; HIGH SPEED; WIND TUNNEL TESTS; AERODYNAMIC CONFIGURATIONS; SCHLIEREN PHOTOGRAPHY; CCD CAMERAS; INTERFEROMETRY; THERMOGRAPHY; DELTA WINGS...