Experimental study on the effect of flare barriers on wave run-up and motion response of a semi-submersible platform

Semi-submersible platforms can suffer slamming damage from extreme waves, making it crucial to improve their airgap performance. To address this issue, this paper proposes an innovative flare barrier that can be attached to the surface of a column at a certain height above the waterline, drawing on bow flares used in ship design. This study conducts a series of experiments to investigate the effectiveness of the flare barrier in mitigating wave run-up and motion response of a semi-submersible platform. The experiment uses irregular waves with a 100-year return period, incident at angles of 180° and 135° to simulate the wave field. To reduce the transient effect, two different wave seeds are considered for each wave-heading condition. The results show that the flare barrier significantly mitigates wave run-up, especially at the height of the lowest edge of the barrier. The addition of flare barrier has no negative effect on surge, heave and pitch response. At incident angle of 180°, it even has a slight mitigation effect on heave and pitch. The mitigation effect is also demonstrated in the power spectral analysis. Considering the wave run-up and motion response, a flare barrier is recommended to mitigate wave run-up on the column and improve the airgap performance under extreme waves.