Abstract
By means of a tripping wire turbulent spots are generated in a conditionally stable laminar boundary layer along a flat plate in a low-turbulence windtunnel. At several vertical and lateral positions the streamwise (U) and vertical (V) velocity components of the spot are measured using anX-shaped hot wire anemometer. The spot's leading edge (LE) and trailing edge (TE) are determined by a high frequency detection criterion.
The derived ensemble averaged shear stress 〈uv〉 shows a remarkable plateau over the last 3/4 of the spot length and over about 1/2 of the spot width, approximately independent of the height above the plate. The measurements suggest that the velocities of the LE and the TE can be explained by simple advection of the active turbulent region. Other mechanisms seem to be responsible for the lateral spread of the spot, as is suggested by the measurements outside the plane of symmetry.
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Bosveld, F.C., Van Haren, J.J.M. & Absil, F.G.J. The measurement of 〈U〉, 〈V〉 and 〈uv〉 inside the turbulent spot using conditionally sampled hot-wire anemometer signals. Appl. Sci. Res. 46, 291–307 (1989). https://doi.org/10.1007/BF01998547
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DOI: https://doi.org/10.1007/BF01998547