Motion response characteristics of a Kyushu-University semi-submersible floating wind turbine with trussed slender structures: experiment vs. numerical simulation
Motion response characteristics of a Kyushu-University semi-submersible floating wind turbine with trussed slender structures: experiment vs. numerical simulation
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DOI：
10.1016/j.oceaneng.2021.109078
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发表时间：
2021-07
影响因子：
5
通讯作者：
Yingyi Liu;Changhong Hu;M. Sueyoshi;S. Yoshida;H. Iwashita;M. Kashiwagi
中科院分区：
文献类型：
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作者：
Yingyi Liu;Changhong Hu;M. Sueyoshi;S. Yoshida;H. Iwashita;M. Kashiwagi
了解浮动式风力发电机的动力学特性对其设计和运行至关重要。由于桁架结构可以减小浮动基础上的波浪荷载/阻力，因此在工业应用中越来越受欢迎。在这方面，了解细长桁架结构对这种FWT运动响应特性的影响是至关重要的。本文发展了一种时域方法来模拟平台甲板上具有多个转子的浮式桁架结构风力发电机的动力学。结合势流理论计算波浪惯性力和Morison条法计算波浪阻力，建立了板-棒混合模型。一种系统的方法和相应的有效工具已经开发出来，用于处理由一组任意长度、直径、方向和位置的细长圆柱形构件组成的浮动桁架结构。将morrison动态求解器引入到FWT动力学的时域求解器中。在九州大学应用力学研究所进行的半潜式三角桁架平台FWT模型实验中，对所提模型进行了验证。仿真结果与实验数据吻合较好，验证了所提方法的有效性。进一步在风浪条件下进行了数值模拟，研究了波浪阻力对FWT动力学的影响。研究发现，在没有流体黏度的情况下，平台运动的共振响应在接近FWT系统固有频率的频率处被激发。通过对泊车工况和运行工况的比较，发现在稳定风存在的情况下，平动浪涌或摇摆运动在其共振频率处被显著激发。这可能是由于风对FWT做的功显著提高了平台的总动能，从而增加了平台在平衡位置的平动浪涌或摇摆速度。采用板杆混合模型可以有效地减少这些不真实的大共振响应。
Understanding the dynamics of an FWT (Floating Wind Turbine) is essential for its design and operation. Since a truss structure can reduce the wave load/resistance on the floating foundation, it becomes more popular in industrial applications. In this regard, knowing the effect of slender members of the truss structure on the motion response characteristics of such an FWT is vital. The present work develops a time-domain method for modeling the dynamics of a floating truss-structure wind turbine with multiple rotors on the deck of the platform. A hybrid panel-stick model is built up incorporating the potential flow theory to calculate the wave inertia force and a Morison strip method to calculate the wave drag force. A systematic methodology, and the corresponding efficient tool, have been developed to deal with the floating trussed structure consisting of a set of slender cylindrical members in arbitrary lengths, diameters, orientations, and locations. The Morison dynamic solver is incorporated into the time-domain solver for the FWT dynamics. The proposed model is validated against a model experiment of a semi-submersible FWT with a triangular-shaped truss-structured platform, which was carried out in RIAM (Research Institute for Applied Mechanics), Kyushu University. Good agreements between the simulation results and the experimental data confirm the validity of the developed method. Further numerical simulations are performed in a set of wind and wave conditions to investigate the effect of wave drag force on the FWT dynamics. It is found that without the fluid viscosity, resonant responses are excited in the platform motions at frequencies that are close to the natural frequencies of the FWT system. Via a comparison between the parked conditions and operating conditions of the FWT, it is found that in the presence of steady wind, the translational surge or sway motion is significantly excited at its resonance frequency. This may be attributed to the work done by the wind to the FWT, which enhances remarkably the total kinetic energy of the platform and consequently increases the translational surge or sway velocity of the platform at the equilibrium position. Applying a hybrid panel-stick model will be effective in reducing all these non-realistic large resonant responses.