Uncertainty analysis of motion-capturing pressure-sensitive paint method based on unsteady surface-pressure measurement on fluttering airfoil

Motion-capturing pressure-sensitive paint (PSP) methods give a pressure map over an unsteady aerodynamic surface. To collect a quantitative pressure measurement using this method, unsteady analysis is important. Due to the unsteady motion of an aerodynamic surface, the luminescent output acquired by a stationary imaging device is a time-dependent value. This creates a time-dependent change in signal-to-noise ratio. An uncertainty analysis is given based on the signal-to-noise ratio of the luminescent output. Unsteady surface pressure over a high aspect-ratio (YXX) wing with 11.5% thickness ratio at 30% chord is considered for analysis. Under Mach 0.8 flow, the YXX wing flutters at 13.7 Hz with a shock oscillation over the surface. With the proposed uncertainty analysis, the overall pressure uncertainty, based off of traditional unsteady pressure taps, of the PSP measurement is given as 3.5 [%]. The measurement region that gives the high signal-to-noise ratio had uncertainty as low as 2.9 [%].