High order force components of a near-wall circular cylinder oscillating in transverse direction in a steady current

Abstract

In the study described in this paper, the drag and lift forces on a circular cylinder undergoing forced oscillation in the transverse direction near a wall were experimentally investigated in a towing tank at a Reynolds number of 2×105. The first four orders of the components of the oscillating drag and lift forces were calculated. The effects of the gap ratio, oscillation frequency, and oscillation amplitude were studied, with particular emphasis on the influence of the nearby wall on the high-order force components. A rigid cylinder was placed near a flat plate, which was used to simulate the seabed, and was towed forward in the water together with the flat plate. The cylinder was forced into sinusoidal oscillation in the cross-flow direction over a wide range of oscillation frequency and amplitude. The hydrodynamic drag and lift forces were measured by three-dimensional force transducers attached to the ends of the cylinder.