Experimental study on the effect of flare barriers on wave run-up and wave loads of a rounded-square column

Extreme waves are prone to produce critical wave run-up on the surface of column and have potential damage to offshore platforms. In order to suppress the wave run-up and improve the air gap performance of the column-stabilized platform, three configurations of flare barriers, namely, monolayer, multi-layer-solid and multi-layer-intermittent flares, were proposed in this study. A series of wave flume experiments were carried out under five focused waves to examine the mitigation effect of different flare barriers attached to a rounded-square column. For each configuration, four incline angles (30°, 40°, 50° and 60°) were considered. The flare barriers have different mitigation effect on the wave run-up. The monolayer flare barrier can completely deflect the uprush flow and generate a strong water jet. The multi-layer-solid flare barrier dissipates the wave run-up by dividing the uprush flow into deflected and unblocked components. The mitigation effect of the multi-layer-intermittent flare barrier on extreme waves is limited. In consideration of the spraying trajectory of water jet and the wave loads on the column, the multi-layer-solid flare barrier with an incline angle of 40° can be recommended for mitigating the wave run-ups on the column under extreme waves.