柔性转子脱落螺旋涡结构的稳定性
Stability of Helical Vortex Structures Shed from Flexible Rotors
摘要：
所提出的调查的动机是需要揭示潜在的转子流体-结构相互作用和涡流动力学之间的连接，以疲劳性能和柔性转子叶片，他们的轮毂，和他们的支持上层建筑的表征。为此，对柔性转子叶片叶尖涡的时间稳定性特性进行了数值研究。采用气动弹性自由涡尾迹方法模拟了螺旋桨叶尖涡及其速度场。一个线性特征值稳定性分析量化的稳定性趋势（增长率与扰动波数）和增长率的时间演变的尖端涡。首先对具有刚性叶片的典型转子及其叶尖涡的产生进行了模拟，以验证本文所采用的稳定性分析。接下来，使用国家可再生能源实验室5 MW参考风力机基础设计来模拟固定式风力机，以研究转子气动弹性对叶尖涡稳定性随时间演变的影响。叶片的灵活性被证明可以降低叶尖涡不稳定对低波数扰动的敏感性，叶片间距也可以降低增长率的大小，并改变增长率峰值对扰动波数的依赖性，所有这些在过去的旋翼机文献中都没有报道过。目前的研究旨在深入了解旋翼机叶尖涡流运动学和稳定性，以量化疲劳载荷及其影响，最大限度地减少不利的叶片涡流相互作用效应，如过度的噪音排放和大叶片振动也影响疲劳性能。
英文摘要：
The presented investigation is motivated by the need to uncover connections between underlying rotor fluid-structure interactions and vortex dynamics to fatigue performance and characterization of flexible rotor blades, their hub, and their supporting superstructure. Towards this effort, temporal stability characteristics of tip vortices shed from flexible rotor blades are investigated numerically. An aeroelastic free-vortex wake method is employed to simulate the helical tip vortices and the associated velocity field. A linear eigenvalue stability analysis is employed to quantify stability trends (growth rate v. perturbation wavenumber) and growth-rate temporal evolution of tip vortices. Simulations of a canonical rotor with rigid blades and its generation of tip vortices are first conducted to validate the stability analysis employed herein. Next, a stationary wind turbine is emulated using the National Renewable Energy Laboratory 5MW reference wind turbine base design to investigate the impact rotor aeroelasticity has on tip vortex stability evolution in time. Blade flexibility is shown to reduce the sensitivity of tip vortex destabilization to low wavenumber perturbations, also blade-pitch reduces growth-rate magnitude and alters the growth-rate peak dependence on perturbation wavenumber, all of which have in the past not been reported in the rotorcraft literature. The current investigation aims to develop insight into rotorcraft tip vortex kinematics and stability to work towards quantifying fatigue loading and its effects, minimizing adverse blade-vortex interaction effects, such as excessive noise emission and large blade vibrations also affecting fatigue performance.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
