考虑叶片影响的风力机塔筒双自由度涡激振动研究

RESEARCH ON TWO-DEGREE-OF-FREEDOM VORTEX-INDUCEDVIBRATION OF WIND TURBINE TOWER CONSIDERINGINFLUENCE OF BLADE

研究叶片影响下风力机塔筒的涡激振动特性。首先,基于计算流体力学(CFD)方法、结构动力学理论以及重叠网格技术,建立塔筒结构的双自由度涡激振动仿真模型,通过与文献试验数据对比,验证模型的准确与适用性。并将该模型用于分析NREL 5 MW风力机塔筒与叶片的双自由度涡激振动。结果表明,采用重叠网格技术和CFD方法相结合,规避了由结构较大振幅所引发的网格畸变和负网格问题,获得了较高的计算精度。相比单塔筒振动工况,考虑叶片对塔筒影响后,两者的尾涡相互干扰与合并现象明显,导致塔筒的双自由运动更为复杂。在约化速度3~11范围内,塔筒横向最大振幅响应约为单塔筒工况的10倍,且振动频率出现“锁定”。

In this study,the vortex-induced vibration characteristics of a wind turbine tower under the influence of the blades are investigated.Firstly,the two-degree-of-freedom vortex-induced vibration simulation model for a column structure is developed based on computational fluid dynamics(CFD)methods,structural dynamics theory,and overset mesh technique.The simulation results of the model is compared with experimental data from domestic and international literature to verify its accuracy and applicability.The model is used to calculate the two-degree-of-freedom vortex-induced vibration of the tower and blades of an NREL 5 MW wind turbine.The results show that the combination of the overset mesh technique and the CFD method avoids the mesh distortion and negative mesh problems caused by the large amplitude of the structure,and achieves high computational accuracy.Compared with the single tower vibration condition,the mutual interference and merging of the tail vortex shedding of the two are obvious after considering the influence of the blades on the tower,resulting in a more complex double-free motion law of the tower.In the approximate speed range of 3 to 11,the maximum transverse amplitude response of the tower is about 10 times that of the single tower case,and the vibration frequency appears to be"locked".