Twin test 3 of TWEET-IE project: Micro devices for enhanced performance of airfoil sections

The present dataset refers to a Twin Test, as part of the TWEET-IE project (TWEET-IE : Twin Wind tunnels for Energy and the EnvironmenT - Innovations and Excellence, HORIZON-WIDERA-2021-ACCESS-03-01 / PR# 101079125), carried out in the wind tunnels of the Politecnico di Milano (POLIMI) and the National Technical University of Athens (NTUA). In this Twin Test, wind tunnel tests were conducted assessing the effect of micro devices for enhanced performance of flatback (FB) airfoil sections. FB airfoils, i.e. thick airfoils with a blunt trailing edge (TE) are used near the root region of modern wind turbine blades, as they provide several benefits compared to their thin TE counterparts. The utter goal of the tests was to investigate the effect of freestream turbulence intensity, Reynolds number and blockage ratio on airfoil performance, 3D flow separation and wake behaviour. Additionally, the effect of flow control devices regarding flow separation control and drag reduction were assessed. The NTUA tests consist of surface pressure measurements, hot-wire measurements, flow visualization with tufts and Stereo Particle Image Velocimetry (SPIV) measurements. The pressure measurements allow for determining the basic performance characteristics of the airfoil, and the hot-wire measurements provide information about the primal shedding frequency.The POLIMI tests consist of surface pressure measurements, force balance and hot-wire measurements. The pressure measurements allow for determining the basic performance characteristics of the airfoil as well as comparing facilities. Next, the force balance measurements provide insights on the effect of the 3D separation to the airfoil loads and the hot-wire measurements allow for determining the spanwise wake correlations. Both fixed and free boundary layer transition cases were tested at a Reynolds number of Re = 1.25M.本数据集为TWEET-IE项目（TWEET-IE：能源与环境双风洞——创新与卓越，项目编号HORIZON-WIDERA-2021-ACCESS-03-01 / PR# 101079125）下的双风洞测试（Twin Test），测试分别在米兰理工大学（Politecnico di Milano, POLIMI）与雅典国立技术大学（National Technical University of Athens, NTUA）的风洞中开展。本次双风洞测试旨在评估用于提升平尾缘（flatback, FB）翼型性能的微型装置效果。平尾缘（FB）翼型即带有钝尾缘（trailing edge, TE）的厚翼型，相较于传统薄尾缘翼型，其在现代风力机叶片根部区域的应用具备多重优势。本次测试的最终目标是探究来流湍流强度、雷诺数（Reynolds number, Re）与堵塞比对翼型性能、三维流动分离及尾迹特性的影响。此外，本测试还评估了流动控制装置对流动分离控制与减阻的效果。雅典国立技术大学的测试包含表面压力测量、热线测量、绒球流动可视化以及立体粒子图像测速（Stereo Particle Image Velocimetry, SPIV）测量。其中，表面压力测量可用于获取翼型的基础性能参数，热线测量则能提供主脱落频率相关信息。米兰理工大学的测试包含表面压力测量、测力天平和热线测量。表面压力测量既可获取翼型的基础性能参数，也可用于不同试验设施间的比对。随后，测力天平测量可揭示三维分离对翼型载荷的影响，热线测量则可用于获取展向尾迹关联特性。本次测试在雷诺数Re=1.25×10^6条件下开展了固定边界层转捩与自由边界层转捩两种工况的试验。