海上环形观光平台内域水体共振响应研究

Study on water wave resonance in the internal zone of a ring-shape sea tourism platform

海洋空间资源开发中,海上观光旅游平台具有较广的应用前景。浮式观光平台可设计为圆环形结构,环形内部区域可以为游艇停泊和亲水场所提供掩护。此类结构与船舶月池结构类似,有内域半封闭水体,也存在水体共振问题。为分析此类结构水体共振响应,评估内域水体掩护条件,对以圆环形为基础增加弦与所截圆弧围成区域平台模型(观光平台)的内域水体共振模态进行模拟。观光平台共有6个特征模态,分布在0.2~0.6 rad/s之间。模态峰值主要分布在中轴线附近位置。平台圆弧和直边界组合导致共振模态分布包括圆形水体环向模态特征和矩形水体模态特征;不同弦心距对应不同内域水体尺寸。随着内域水体尺寸减小,模态响应频率向高频移动;通过增加环形宽度和设置主迎浪面在突出平台位置,可降低波浪透射,从而减弱内域水体共振响应幅值。工程设计中可调整上述参数降低内域水体共振幅值,达到较好的泊稳条件。

From all offshore structures for further ocean space development,the prospect of the ocean tourism platform is clear and expected.The floating tourism platform can be designed in a ring shape.The inner zone of the ring can provide shelter for yachts and water recreation.From scientific perspective,such structures have semi-closed water zones which are similar to moonpools.The water wave may resonate and be enlarged in the inner zone under specific conditions compared with normal ones.To estimate the resonate response of the kind of floating tourism platforms,the resonant mode analysis was conducted on a new concept model platform composed with straight and circular boundaries.It shows six typical modes varying in the range of 0.2~0.6 rad/s.The distribution of peak responses focuses nearby the central axis mostly.The composed boundaries induce the resonant mode with characters of both the circular zone and rectangular zone.Different chordal center distances correspond to different water dimensions of the inner domain.The resonant frequencies will increase gradually as the water size becomes smaller.Wave transmission can be reduced by increasing the width of the ring-shape structure or adjusting the incident wave direction to the step part of platform.It is recommended to reduce resonance wave height in the inner zone by considering the effect of above parameters.