Second‐Order Diffraction Loads on Truncated Cylinders

A solution, exact to the second‐order in wave steepness, is presented for the hydrodynamic loading on a stationary, truncated circular cylinder in water of arbitrary uniform depth. Two situations are considered: the structure may either be completely submerged and resting on the seabed, or partially immersed in the free surface. The method employed to calculate the second‐order forces and moments due to the second‐order velocity potential does not involve the explicit calculation of this potential. Instead, the hydrodynamic loading components due to this potential are found by applying Green's second identity and solving a series of linear radiation problems at the second‐order wave frequency. Numerical results are presented for several example structures that illustrate the relative importance of the second‐order effects over a range of wave periods. In general, the components that are explicitly due to the second‐order potential are found to result in the dominant loading effects at that order.