Hydrodynamic Forces on Large Cylinders in Oscillatory Flow

Abstract

The hydrodynamic forces on a cylinder exposed to oscillatory flow have been determined at Reynolds numbers (Re) in the range 2.5×105 to 1.0×106 (supercritical and transcritical regimes) and Keulegan‐Carpter (KC) numbers in the interval from 1 to 16. One smooth and two rough cylinders were tested. Inline force coefficients and rms lift coefficients are given as a function of KC, Re, and surface roughness. Time series of both force components are shown, and different flow regimes are identified. These force traces are linked to characteristic vortex shedding modes in different KC‐intervals. Both force components are found to vary considerably in the KC‐range under investigation, with the transverse force sometimes being as large in magnitude as the in‐line force.