Affiliations: California Institute of Technology,1200 East
California Boulevard, Pasadena, CA 91125, USA | University of California, 9500 Gilman Pr., La Jolla,
San Diego, CA 92093-0411, USA
Abstract: Experimentally produced two-dimensional flows have become possible
in recent years due to the invention of Liquid Film Tunnel (LFT) in 1987 by
Gharib and Derango. This simple, inexpensive, yet powerful device, which we
have improved extensively over the last decade, can generate a variety of
flows. Liquid (soap) films can be visualized through light interference effects
produced by small variations in the film thickness. Flow-disturbing objects
such as cylinders, wedges, and air bubbles create these variations.
Monochromatic visualization of these thickness variations will render
phenomenally accurate graphic information about the flow patterns thus
produced. Under a polychromatic light, these interference effects can be
spectacular, due to reflection of different colors by different isothickness
regions.
Keywords: liquid (soap) film tunnel (LFT), two-dimensional flow, refraction