On the wavy flow past a weakly submerged horizontal circular cylinder at low Keulegan–Carpenter numbers

Abstract

The interaction of regular waves with a weakly submerged horizontal circular cylinder at Keulegan–Carpenter KC numbers up to 2.5 is studied by means of numerical simulations, solving the two-phase flow Navier–Stokes equations with the Finite Volume method and the Volume of Fluid interface capturing method. Experimental data from laboratory tests conducted in the past by one of the authors are used as reference data. The study is focused on the surface wave transformation, on the flow field in the near region and on the loads on the cylinder. The interest is driven on the spectral content of the transmitted waves at higher order frequencies and on the non-linear features of the wave reflected by the cylinder. The flow field in the near-body region is analyzed in terms of vortex onset, development and detachment, and correlating pressure pulses with the vorticity field at the cylinder surface. Inviscid flow simulations are carried out too, to evince the origin of higher order terms either from the free surface or from the viscous terms in the momentum equations. The steady streaming around the cylinder is analyzed, including its variability along the cylinder surface and its relationship with the vortex cores generated at the body surface.