Micro thermal anemometer (µTA) for turbulence measurement: development, fabrication and characterization

The present work provides details on the fabrication and the characterization of a micro thermal anemometer for measuring velocity fluctuations in turbulent flows. This device is based on a freestanding thin platinum wire of 60 µm × 0.2 µm × 1.5 µm acting as sensing element, placed in the middle of a 900 µm length bridge and supported by a silicon structure. A discussion is provided on the designing steps and the manufacturing process relying on micro fabrication techniques. A series of flow velocity measurements was conducted in a turbulent boundary layer to evaluate the response of this sensor. The results are discussed and compared with conventional hot wire anemometry measurements and semi-empirical models to highlight the relevance of this new sensor for turbulence studies.