@article{oai:nagoya.repo.nii.ac.jp:00030670, author = {Matsui, Tetsuya}, issue = {2}, journal = {Memoirs of the School of Engineering, Nagoya University}, month = {Mar}, note = {Second-order wave effects on the behaviour of ocean platforms have been studied theoretically and experimentally, with particular interest in sum-frequency oscillations of tension leg platforms. These investigations are reviewed in this paper based on the recent works by the author and his co-workers[1)-3)].The paper consists of two parts. In Part 1, the complete second-order diffraction theory is formulated for predicting second-order wave loads on arbitrary three-dimensional bodies floating in regular waves. Green's second identity is exploited to express the secondorder forces due to the second-order potential in terms of the first-order quantities alone. The resulting expressions for the second-order forces are evaluated from numerical first-order solutions based on the hybrid integral-equation method. Numerical examples are presented for a variety of geometries and compared with previous theoretical and numerical solutions as well as with model test results. Agreement is seen to be satisfactory, illustrating the validity of the proposed approach. In Part 2, the results are presented of the model tests which were performed in regular waves to measure the second-order sum-frequency oscillations and tether forces of tension leg platforms. These test results are used to validate the predictions based on the complete second-order diffraction theory developed in Part 1. It is found that the vertical-plane motions and resulting tether forces of the tension leg platforms include second-order sum-frequency resonant components which are comparable in magnitude with first-order wave-frequency responses. The correlation between predicted and measured results is overall satisfactory, confirming the validity of the theoretical predictions.}, pages = {224--266}, title = {Second-order wave effects on ocean platforms: theory and experiment}, volume = {44}, year = {1993} }