The effects of nose-shape and upstream flow separation on the wake of a cylindrical square-backed body.

• Water channel experiments were conducted on cylindrical square-backed bodies. • Two different nose configurations were tested. • Separation induced by the nose generated greater asymmetry in the wake. • Greater separation over the nose inhibited coherent vortex shedding. • The upstream, overbody and wake flows exhibited Reynolds number sensitivity. An experimental study was conducted on flow around two-dimensional, square-backed bluff bodies in the presence of a ground plane. Two frontal geometries were tested: one with significant leading-edge separation and one without. The extensive leading-edge separation was found to induce significant asymmetry in the time-averaged wake. One-sided shedding from the top trailing edge was found to occur in the absence of significant separation, but broad-spectrum turbulence was found to be responsible for much of the fluctuating energy. More pronounced upstream separation was found to further inhibit regular shedding of large-scale structures in the wake. Over the range considered, a degree of Reynolds number sensitivity was observed, with the boundary layer along the ground plane separating upstream of the body at low Reynolds numbers. The effect of increasing the ground clearance was also considered, which weakened the leading-edge separation whilst increasing the prominence of vortex shedding. [ABSTRACT FROM AUTHOR]