Space–time VMS computation of wind-turbine rotor and tower aerodynamics
Space–time VMS computation of wind-turbine rotor and tower aerodynamics
复制标题
风力涡轮机转子和塔架空气动力学的时空 VMS 计算
DOI：
10.1007/s00466-013-0888-x
复制
发表时间：
2013
影响因子：
4.1
通讯作者：
Casey P. Habluetzel
中科院分区：
文献类型：
--
作者：
K. Takizawa;T. Tezduyar;Spenser McIntyre;Nikolay Kostov;Ryan S. Kolesar;Casey P. Habluetzel
提出了风力机旋翼和塔架空气动力学的时空变分多尺度计算方法。转子几何形状为NREL 5 MW海上基线风力涡轮机的几何形状。我们用给定的风速和指定的转子速度进行计算。由于大雷诺数和旋转湍流，计算具有挑战性，并且计算正确的扭矩需要精确细致的数值方法。由于转子和塔架之间的快速旋转相对运动，塔架的存在增加了计算挑战。ST-VMS方法是变形空间域/稳定ST（DSD/SST）方法的基于残差的VMS版本，并且也被称为“DSD/SST-VMST”方法（即，使用VMS湍流模型的版本）。在计算方法中嵌入的稳定化参数，我们使用一个新的元素长度定义的扩散主导的限制。DSD/SST方法是作为一种通用的移动网格方法引入的，用于计算具有移动界面的流动，需要网格更新方法。网格更新通常包括尽可能长时间地移动网格并根据需要重新划分网格。在这里报告的计算中，使用NURBS基函数来暂时表示转子运动，使我们能够准确地表示与该运动相关的圆形路径，并指定与沿着这些路径的不变速度相对应的恒定角速度。此外，时间NURBS基函数用于表示计算的体积网格的运动和变形，也在重新网格化。我们将其命名为“ST/NURBS网格更新方法（STNMUM）”。STNMUM在计算机时间和存储方面提高了计算效率，并且在能够改变计算的时间步长方面提高了计算灵活性。我们在叶片表面附近使用薄层元件，这些薄层元件与转子一起进行刚体运动。我们比较了有塔和没有塔的计算结果，我们还比较了使用NURBS和线性有限元基函数在网格运动的时间表示。
We present the space–time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called “DSD/SST-VMST” method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of flows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this “ST/NURBS Mesh Update Method (STNMUM).” The STNMUM increases computational efficiency in terms of computer time and storage, and computational flexibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion.