框架式浮鱼礁波浪水动力特性数值模拟研究

摘要

中国海洋牧场建设以投放人工鱼礁为主,人工鱼礁分为沉式鱼礁和浮鱼礁,而浮鱼礁能够较好地适应淤泥质近海养殖.以框架式浮鱼礁为研究对象,采用有限单元法和集中质量点法建立波浪作用下的水动力数值模型,模拟浮鱼礁在海水中实际运动情况.对比分析了不同波高(1.5、2、2.5和3 m)、水深(8、9、10、11和12 m)条件下的框架浮体运动轨迹、最大偏转角度以及锚绳受力特性,研究分析了浮鱼礁设计与实际应用时,目标海域潮位变化和波浪要素共同作用的影响.结果显示:框架浮体水平方向偏移、偏转角度、锚绳最大拉力均随波高增大而增大,近似于线性变化,且均随水深增大而减小,存在浮鱼礁不受波浪影响的临界水深,此时浮鱼礁上端至水面的距离与水深的比值约为0.5,当超过0.5时,水深变化对浮鱼礁水平位移、偏转角度和锚绳受力几乎没有影响.研究结果可为新型人工浮鱼礁的设计与投放提供参考.%The construction of marine ranch in China focuses on the delivery of artificial reefs. Artificial reefs are divided into sunken reefs and floating reefs. Floating reefs can better fit mucky-soil offshore farming. This article takes frame-type floating body as the research target,and uses finite element method and centralized mass point method to set up hydrodynamic numerical model under wave action,thus to simulate the actual movement of floating reefs in seawater. The movement trajectory,maximum deflection angle and anchor rope force characteristic of the frame-type floating body under different wave heights (1.5,2,2.5 and 3 m) and water depths(8,9,10,11 and 12 m) were compared and analyzed;and the impact of tidal levels in target sea area and the interaction of wave elements of floating reefs in the design of floating reefs and its practical application were studied and analyzed. The results showed that:the horizontal displacement distance angle, maximum deflection angle and anchor rope force characteristic of the frame-type floating body increase with the increase of wave height,which is similar to a linear change,and decrease with the increase of the water depth. There is a critical depth at which the floating reefs are not affected by waves. The ratio of the distance from the top of the floating reef to the water surface and distance from the top of the floating reef to the depth of water is about 0.5. When this ratio is over 0.5,the change of water depth has almost no effect on the horizontal displacement distance,deflection angle and anchor rope force of the floating reefs. The results of this study provide references for the design and deployment of new artificial floating reefs.