A Numerical and Physical Comparison of a Geometrically Simple Fixed and Floating Oscillating Water Column

A truncated hollow vertical circular cylinder provides a useful conduit for analysing the behaviour and performance of an offshore Oscillating Water Column wave energy device. This paper presents the preliminary results from a numerical and physical modelling study of a fixed thin-walled and a floating thick-walled cylinder, together with the numerical modelling of a thick-walled fixed cylinder of the same internal diameter. Comparisons of the measured pressures internal to the column, and external to the body in the case of the floating model, are made with the predictions obtained using the numerical boundary-element model WAMIT. Body motions are also given for the floating model. The numerical modelling enables a comparison to be made between the diffraction pressure on a thin and thick walled cylinder of the same internal diameter.