深水浮式平台锚泊静动力等效截断的模型试验方法研究

Physical model tests of deepwater floating platform play a key role in solving practical engineering problems and in scientific research. Limited by the dimension of wave basins, the hybrid model testing method is widely applied to conduct model tests of deepwater floating platforms. However, based on traditional hybrid model testing method, the predictions for Low Frequency (LF) motion response of deepwater floating platforms are not good enough because of the discrepancy of dynamic characteristic between full-depth and truncated mooring system. Thus, the model testing method of deepwater floating platform by truncation of mooring system based on static and dynamic equivalence is proposed in this research project. Both static and damping equivalence are considered while designing the truncated mooring system to make sure that the predictions of platform motion response are correct and effective. The main research contents are as follows: 1. A simplified calculation model for predicting mooring-induced damping is created, by which the friction between mooring line and seabed could be considered. Furthermore, the corresponding program is developed. And then, physical model tests are conducted in order to verify the effectiveness of the simplified algorithm. 2. Design criteria of truncated mooring system is proposed based on both static and damping equivalence. Subsequently, the corresponding modular optimization program is developed. Proper intelligence algorithm and optimization parameters are chosen for each type of deepwater mooring system. 3. The applicability, the feasibility and the validity of the model testing method by truncation of mooring system based on static and dynamic equivalence is discussed through numerical simulation and physical model tests. Finally, a set of true and reliable method and technology would be established for predicting motion responses of deepwater floating platforms.

深水浮式平台物理模型试验在解决实际工程问题和科学研究中起关键作用。受水池空间尺度限制，通常应用被动式混合模型试验方法进行试验。然而传统方法中，由于截断锚泊系统和全水深锚泊系统的动力特性差异，深水浮式平台的低频响应预报结果误差偏大。针对上述问题，本项目提出锚泊静动力等效截断的深水浮式平台试验方法，在截断锚泊设计中同时考虑锚泊静回复力和阻尼等效，从而保证平台运动响应预报结果的正确性。主要研究内容如下：1.建立考虑海底摩擦力的锚泊阻尼简化计算模型，开发相应程序，并通过模型试验验证该简化算法的有效性；2.提出锚泊静力和阻尼同时等效的截断锚泊设计原则，开发相应模块化优化程序，并针对不同型式锚泊系统选取各自适宜的智能算法和优化参量；3.结合数值模拟和物理模型试验讨论锚泊静动力等效截断试验方法的适用性、可行性和正确性。通过本项目研究，预期建立一套真实可靠预报深水浮式平台运动响应的物理模型试验方法与技术。

深水浮式平台模型试验在解决实际工程问题和科学研究中起关键作用。受水池空间尺度限制，通常应用被动式混合模型试验方法进行试验。然而传统方法中，由于截断锚泊系统和全水深锚泊系统的动力特性差异，深水浮式平台的低频响应预报结果不够理想。此外，数值重构过程复杂且难以直接观测实验现象。因此本项目提出了锚泊静动力等效截断的深水浮式平台试验方法，在截断锚泊设计中同时考虑了锚泊静回复力和阻尼等效，可以确保平台运动响应预报结果的正确性。首先，本项目建立了可考虑海底摩擦力的锚泊阻尼简化计算模型，开发了相应计算程序，并通过模型试验验证了该算法模型的有效性；其后，本项目提出了锚泊静力和阻尼同时等效的截断锚泊设计原则与方法，开发了相应模块化智能优化程序，并针对不同型式锚泊系统选取各自适宜的智能算法和优化参量；然后，通过数值模拟讨论了锚泊静动力等效截断试验方法在不同型式深水浮式平台、不同型式锚泊系统、不同水深情况等条件下的适用性，并通过物理模型试验验证了锚泊静动力等效截断试验方法的可行性和正确性；最终，本项目建立了一套可以真实有效进行深水浮式平台运动响应预报的物理模型试验方法和流程，对我国海洋工程深远化起到了重要的支撑作用。