Flow visualization and velocity measurements in the turbulent boundary layer of a laboratory shallow channel

摘要

Flow visualizatio and velocity easurements were obtained in an open channel of 20 m length and 1 m width and 0.08 m depth, with a Reynolds number of 12000. The test section had a glass lateral wall and acrylic bottom wall to allow optical access. The images of dye injected at the bottom of the channel were recorded with two video cameras and velocities were measured with a hot film anemometer. The video cameras and the velocity measurements were synchronized; correlation of the image and traced velocity were processed in a computer. When the velocity sensor was located at about 50 wall units, the velocity increased when a shear layer was passing behind it. The image from the plane and side views were also correlated in order to analyze some aspects of the tridimensionality of the flow structures.