Uncertainty estimates for pressure sensitive paint measurements

Abstract

A recently introduced surface pressure measurement technique for aerodynamic applications uses pressure sensitive luminescent coatings. The primary measurable is luminescent light intensity, but the determination of pressure also requires the measurement of other variables, such as a reference light intensity and surface temperatures. Each of the primary measurables is associated with an error that contributes to the uncertainty of the pressure computed from all inputs. This paper investigates these contributions to the resultant uncertainty, both in fundamental terms and in terms of commonly used wind tunnel parameters. The uncertainty is sharply dependent on both freestream and local flow conditions, such that a simple global characterization of error magnitude does not seem to be practical. Spatial surface temperature variations and temperature differences between reference and run conditions may significantly affect the results.