The numerical and experimental investigations of the near wake behind a modified square stay-cable

The near wake structure, the wake-flow characteristics and the drag coefficients behind a modified square stay-cable (MSC) with sinusoidal variations of the cross-section area along the spanwise direction are investigated experimentally and numerically. The Reynolds numbers are chosen as 100 and 500 for the laminar flow and 6 000 and 22 000 for the turbulent flow. The detailed near wake structures, the velocity fields and the force coefficients for the MSC are captured, the effect of the Reynolds number on the flow structure for the MSC is studied. The numerical and experimental investigations show that the free shear layers from the leading edge are widened and prolonged and then roll up into vortices further downstream the MSC, unlike a straight square stay-cable (SSC) under the same flow conditions. As a result, the distinct mean drag reduction and the fluctuating lift suppression are observed for all Reynolds numbers, a drag reduction of at least 15.8% and the rms lift coefficient reduction of up to 95% are observed, as compared with the case of a straight square stay-cable at .