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A Flexible Hot-Film Sensor Array for Underwater Shear Stress and Transition Measurement

A flexible hot-film sensor array for wall shear stress, flow separation, and transition measurement has been fabricated and implemented in experiments. Parylene C waterproof layer is vapor phase deposited to encapsulate the sensor. Experimental studies of shear stress and flow transition on a flat p...

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Detalles Bibliográficos
Autores principales: Sun, Baoyun, Wang, Pengbin, Luo, Jian, Deng, Jinjun, Guo, Shiqi, Ma, Binghe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6209982/
https://www.ncbi.nlm.nih.gov/pubmed/30326635
http://dx.doi.org/10.3390/s18103469
Descripción
Sumario:A flexible hot-film sensor array for wall shear stress, flow separation, and transition measurement has been fabricated and implemented in experiments. Parylene C waterproof layer is vapor phase deposited to encapsulate the sensor. Experimental studies of shear stress and flow transition on a flat plate have been undertaken in a water tunnel with the sensor array. Compared with the shear stress derived from velocity profile and empirical formulas, the measuring errors of the hot-film sensors are less than 5%. In addition, boundary layer transition of the flat plate has also been detected successfully. Ensemble-averaged mean, normalized root mean square, and power spectra of the sensor output voltage indicate that the Reynolds number when transition begins at where the sensor array located is 1.82 × 10(5), 50% intermittency transition is 2.52 × 10(5), and transition finishes is 3.96 × 10(5). These results have a good agreement with the transition Reynolds numbers, as measured by the Laser Doppler Velocimetry (LDV) system.