Experimental study on the wave run-up and air-gap response of a three-column semi-submersible platform

摘要

The hydrodynamic responses, characterized by 6 degrees of freedom (DOF) motions, wave run-up and air-gap of a three-column semi-submersible platform in random sea are experimentally investigated. Irregular waves representative of a 100-yr typhoon were used as the incident wave field and the actions of wind and current are included. It was found that extremely large slow-drift surge motions occur under irregular waves, while the low-frequency pitch motions are relatively small which were believed to be remarkable for the deep-draft semi-submersible. A wavelet cross bicoherence analysis was applied to investigate the extreme wave run-up responses. The high-frequency components in the extreme wave run-ups were found to be from the quadratic phase coupling between the dominant response frequencies of the incident waves, heave motion, and pitch motion.