Abstract
The formative process of the oil flow pattern in a fully developed turbulent boundary layer on a flat plate has been photographed by using a shadowgraph technique. Results have showed as follows.
At first, gradual risings of oil which looks like unstable waves appear on a plain oil film surface. Each rising moves downstream, increasing its height from a specimen surface, being more wavy and then constructs a "V" shapes. At the next stage, a oil spot appears at the downstream top of the "V" shape, where is highist part in oil thickness, and then oil flow out from the spot toward the stream-wise direction, constructing a short oil filament. At the last stage, by the combination of many. short oil filaments, a long oil filament is formed. The phenomena described above resembles closely to "bursting" in a turbulent boundary layer.
