NOSTRUM - Aerodynamic Polar Dataset for Wind Turbine Airfoils

This dataset contains the aerodynamic polars and airfoil coordinate files used for wind turbine aerodynamic analyses within the NOSTRUM project, Optimizing Floating Offshore Wind Turbines for Use in the Mediterranean Sea. For each airfoil, the dataset includes a dedicated folder containing the airfoil geometry coordinates and the corresponding aerodynamic polars over an angle-of-attack range from −15° to 25°, sampled with a 2° increment. Polars are provided for four Reynolds numbers representative of large-scale wind turbine applications: 6, 9, 12 and 18 milions.

The airfoil polars were generated through a MATLAB-based workflow coupled with ANSYS ICEM CFD and ANSYS Fluent. Starting from the original airfoil coordinates, each profile was interpolated along its curvilinear abscissa to obtain a refined geometric description suitable for mesh generation. A structured 2D computational mesh was then generated automatically in ICEM CFD, with dedicated refinement in the leading-edge, trailing-edge, and wall-normal regions in order to ensure adequate resolution of the boundary layer and near-edge flow features. The aerodynamic simulations were subsequently carried out in Fluent under steady incompressible conditions using the Transition SST turbulence model.

The simulations were performed assuming a reference chord of 1 m, a free-stream velocity of 12 m/s, and a turbulence intensity of 1%, while the dynamic viscosity was adjusted consistently with the target Reynolds number. For each angle of attack, lift and drag coefficients were extracted from the converged solution history and evaluated from the final portion of the monitored signal in order to reduce the influence of residual transients. The resulting Cl and Cd values form the aerodynamic polar database distributed in this archive.

In addition to reference airfoils, the dataset also includes optimized airfoils developed within the multi-fidelity design activity documented in the report M5_D4_Optimized Airfoil Design using Multi-Fidelity Analyses.pdf, included in NOSTRUM - Optimizing Floating Offshore Wind Turbines for Use in the Mediterranean Sea - Technical Reports - Part 2 (DOI: 10.5281/zenodo.18620593). The dataset is intended to support reproducible aerodynamic analysis, blade design studies, and comparative assessment of airfoil performance for large offshore wind turbines, with particular relevance to Mediterranean operating conditions.

本数据集包含NOSTRUM项目（面向地中海应用的漂浮式海上风力发电机优化）中用于风力发电机空气动力学分析的空气动力学极曲线（aerodynamic polars）与翼型坐标文件（airfoil coordinate files）。针对每一种翼型，本数据集均设有专属文件夹，内含该翼型的几何坐标，以及攻角（angle-of-attack）范围为-15°至25°、步长为2°的对应空气动力学极曲线。极曲线对应4种适用于大型风力发电机应用场景的雷诺数（Reynolds numbers）：6、9、12与18百万。

本数据集的翼型极曲线通过基于MATLAB的工作流生成，该工作流耦合了ANSYS ICEM CFD与ANSYS Fluent软件。从原始翼型坐标出发，研究人员首先沿曲线横坐标（curvilinear abscissa）对每个翼型剖面进行插值，以获得适用于网格生成（mesh generation）的精细化几何描述；随后在ICEM CFD中自动生成结构化二维计算网格（structured 2D computational mesh），并对翼型前缘（leading-edge）、后缘（trailing-edge）及壁面法向区域（wall-normal regions）进行专属网格加密，以确保边界层（boundary layer）与近壁流动特征（near-edge flow features）具备足够的分辨率。后续的空气动力学仿真在Fluent中开展，采用定常不可压缩流动条件（steady incompressible conditions），并使用Transition SST湍流模型（Transition SST turbulence model）。

仿真设定参考弦长（reference chord）为1m、来流速度（free-stream velocity）为12m/s、湍流强度（turbulence intensity）为1%，同时动力粘度（dynamic viscosity）根据目标雷诺数进行相应调整。针对每个攻角，研究人员从收敛的求解历史（converged solution history）中提取升力系数（Lift Coefficient, Cl）与阻力系数（Drag Coefficient, Cd），并通过监测信号的最终区段进行数值计算，以降低残余瞬态过程（residual transients）的影响。由此得到的Cl与Cd数值构成了本归档文件中分发的空气动力学极曲线数据库。

除参考翼型外，本数据集还包含在多保真度设计活动（multi-fidelity design activity）中开发的优化翼型，相关设计活动的细节记录于报告《M5_D4_Optimized Airfoil Design using Multi-Fidelity Analyses.pdf》中，该报告收录于《NOSTRUM - Optimizing Floating Offshore Wind Turbines for Use in the Mediterranean Sea - Technical Reports - Part 2》（DOI: 10.5281/zenodo.18620593）。本数据集旨在支撑大型海上风力发电机的可复现空气动力学分析、叶片设计研究以及翼型性能对比评估，尤其适配地中海的运行工况。