EFFECT OF ROUNDING SIDE-CORNERS ON AERODYNAMIC FORCES AND TURBULENT WAKE OF A CUBE PLACED ON A GROUND PLANE

This paper describes the experimental study of a flow past a cube with rounded side-corners placed in a ground plane under the condition of delta/D<1, where delta is the thickness of the upstream boundary layer. The experiment was carried out in an N.P.L. type wind-tunnel having a working section of 500 mm x 500 mm x 2,000 mm at a Reynolds number 4.74 x 10(4). The surface-pressure distribution on the cube was measured, and the drag coefficient was determined from the surface-pressure distribution. Furthermore, two kinds of vortices generated around the cube were observed. The distribution of velocities and turbulent intensities in the turbulent wake behind the cube with rounded side corners were measured, and compared with those of a two-dimensional cylinder. As a result, it was found that the drag coefficient decreases rapidly in the range of 0 less-than-or-equal-to 2R/D less-than-or-equal-to 0.3, and the Strouhal number for the arch-vortex shedding increases as the radius of the corner increases.