Fabrication and static calibration of double-layer thermal film sensor for fluid wall shear stress measurement

A double-layer flexible sensor array with an active thermal insulation method for fluid wall shear stress was fabricated in this study and evaluated experimentally. Static calibration of the sensor was studied in both wind and water tunnels and the experimental results reveal that the sensor's static performance was improved by active thermal insulation. Compared to single-layer methods, the static sensitivity of the proposed double-layer sensor is increased by approximately 48% in a wind tunnel and 13% in a water tunnel. Additionally, consistent deviations in the static calibration coefficients of sensors with different basic parameters were clearly compensated in the wind tunnel. The calibration coefficient deviation of the sensors was reduced from 57% in single-layer mode to 5% in double-layer mode.