Turbulent Boundary-Layer along a Streamwise Bar of a Rectangular Cross Section Placed on a Flat Plate

抄録

Three-dimensional turbulent boundary layer developing along a long streamwise bar of a rectangular cross section (60 mm × 20 mm) placed on a flat plate was investigated experimentally. Two different wall configurations are possible by placing the longer sides of a rectangle perpendicular or parallel to the plate surface. This class of turbulent boundary layers is made complicated by secondary currents which inevitably arise near the streamwise corners. Experimental results obtained for both wall shapes are described mainly concerning isovels, lines of constant turbulence intensity, secondary currents measurements by vortex-meter, distributions of wall shear stress and total drags. Considerations are made on the velocity profiles in a plane of flow symmetry where secondary currents flow toward the wall, and a self-preserving distribution in the outer layer is proposed.