考虑黏性效应的半潜浮式风力机动力特性研究

对半潜浮式风力机动力特性进行研究，推导考虑黏性阻尼的动力学方程及传递函数。对黏性效应的影响及其计算方法进行探讨，对比附加阻尼矩阵法、Morison单元法的优缺点，并提出考虑黏性阻尼效应水动力计算的混合法，在此基础上对半潜浮式风力机气动-水动-锚泊全耦合动力响应进行分析。结果表明：黏性效应主要影响共振周期附近的响应值，在数值分析时不可忽略；附加阻尼矩阵法在考虑水平面内运动黏性阻尼时有所不足，且无法考虑黏性效应对共振周期的影响，Morison单元法在考虑垂荡、转动黏性阻尼时有所不足，混合法是考虑黏性阻尼水动力计算的更有效方法；该半潜浮式风力机垂荡和纵摇响应主要受波浪控制，而水平面内运动受风、浪、流联合作用的影响；浮式风力机运动和加速度的最危险工况可发生在发电工况时，最大锚链张力发生在极端环境条件时。

RESEARCH ON DYNAMIC CHARACTERISTICS OF SEMI-SUBMERSIBLE FLOATING WIND TURBINE CONSIDERING VISCOUS EFFECT

The dynamic characteristics of the semi-submersible floating wind turbine are researched in this paper. The dynamic equation and the transfer function considering viscous damping are derived. The effect of viscosity on dynamic response and the calculation method of viscous damping are studied. The advantages and disadvantages of the additional damping matrix method and the Morison method are compared. And a hybrid method considering viscous damping is proposed. On this basis, the dynamic response of the semi-submersible floating wind turbine considering the full coupling of aerodynamics, hydrodynamics and mooring is analyzed. The results show that the viscous effect mainly affects the response value near the resonance period and it cannot be ignored in numerical analysis. The additional damping matrix method is insufficient when considering the viscous damping of motion in the horizontal plane and it cannot consider the effect of viscosity on the resonance period. The Morison method is deficient in calculating the heave and pitch response considering the viscous damping effect. The hybrid method is a more effective method for hydrodynamic calculations considering the viscous effect. The heave and pitch responses of the semi-submersible floating wind turbine are mainly controlled by waves, while the motion responses in the horizontal plane are affected by the combined action of wind, wave and current. The most dangerous conditions for motion and acceleration of the floating wind turbine may occur during power generation. The maximum tension of the anchor chain occurs under extreme environmental conditions.