Abstract
Laminar-Turbulent transition of a boundary layer forced by a jet in the inlet region of a circular pipe was experimentally investigated. The jet was inserted radially from a small hole in the inlet region into the pipe flow periodically. Isolated turbulent patches were formed from the jets, and then they propagated downstream. Axial and radial velocity components were measured by a hot-wire anemometer. Mean and fluctuating velocities and intermittency function were ensemble-averaged. The contour maps of the intermittency were drawn. When an interval between turbulent patches is closer, the growth of turbulent patches is weaker than that of the longer interval. A radial velocity with opposite direction at leading and trailing edges may affect the growth.
