Validation of Second-order Analysis In Predicting Diffracted Wave Elevation Around a Vertical Circular Cylinder

In the present paper, the focus is on water wave diffraction around a single, fixed vertical circular cylinder subjected to monochromatic incoming waves. The study involves waves of different steepnesses and periods. The wave elevation at various locations around the cylinder is considered. Numerical simulations of first and second order diffraction, by means of potential theory, using an industry standard numerical tool (WAMIT, 1995) are conducted. A convergence study of the second order diffraction is presented, and numerical results are compared to model test data from the MARINTEK Towing tank. Moreover, the validity of the second-order approach is investigated. Magnitudes of thirdand higher order contributions are evaluated from the measurements in the higher harmonics as well as in the basic harmonic and the mean set-up.