Wind tunnel measurement on a wind turbine blade tip with flush-mounted MEMS pressure and acoustic sensors

Abstract

Over 200 pressure Micro-Electro-Mechanical Systems (MEMS) sensors and more than 1000 acoustic MEMS sensors were installed on a wind turbine tip model with a length of 1995 mm and a root chord length of 826 mm. Measurements were conducted in the closed test section of the Low-Speed Wind Tunnel DNW-NWB in Braunschweig, with test velocities ranging from 40 to 70 m/s and geometric angles of attack between –7 ◦ and 25 ◦ . Flow transition was detected using infrared thermography, while wall shear stress at the trailing-edge region was measured with capacitive shear stress sensors, and flow velocity was obtained with a pressure rake. The MEMS measurements clearly identified key flow characteristics, such as flow transition and flow separation.