复杂地形条件下浮式栈桥运动响应的频域分析

Analysis of Motions Responses of Floating Bridge over Rough Bottom Regions in Frequency Domain

为了研究复杂地形条件下浮式栈桥的运动响应,并探讨波浪圆频率及浪向角等因素对浮式栈桥运动响应的影响。论文利用势流理论及波浪绕射/辐射理论对浮式栈桥所处流场的速度势进行了分析,并对复杂海底地形条件下浮式栈桥的运动特性进行了水池试验和数值模拟研究。基于水动力计算软件AQWA,将复杂海底地形作为一个潜体置于海底,进而考虑其与上部浮体及波浪的水动力干扰,从而建立了海底地形-浮式栈桥-波浪水动力耦合计算模型,模拟计算了浮式栈桥在复杂地形条件下的运动响应,并通过水池试验对数值计算结果进行了验证。结果表明,耦合计算模型能够较为准确地预报复杂地形条件下浮式栈桥的运动响应;复杂海底地形条件下浮式栈桥各桥节的运动响应有较显著的差异,且桥节RAOs随浪向角的变化曲线与平坦海底地形条件下的RAOs曲线有一定差异;浅水环境下海底地形对浮式栈桥运动响应和波浪传播特性的影响不能忽视。

Potential flow theory and dif＆action/radiation wave theory are applied in numerical simulation of motion response of a floating bridge （FB） over rough seabed,as well as model tests are carried out in a wave tank. Hydrodynamic interaction between the floating structure and waves is calculated with the software AQWA. A hydrodynamic model of rough seabed-FB-wave is built to evaluate motion response of the FB over the rough bottom, and is validated through model tests. It is shown that the hydrodynamic model can well forecast motions of the FB. Differences in RAOs exist between pontoons, while RAOs of each pontoon over the rough bottom are different from that over the flat bottom. Influence of the seabed on motion response of the FB and the wave transmission cannot be ignored in shallow water.