Dynamic calibration of a high-resolution wind tunnel model for ultra-low-range fluctuating surface pressure measurement

Abstract Measuring surface pressures in a low-speed wind tunnel which are well-resolved in both space and time can be particularly challenging. A technique has therefore been developed for the simultaneous dynamic calibration of large numbers of pressure tappings on a wind tunnel model. A portable, variable-volume plenum is used to calibrate the model in situ . A forcing function consisting of sequential sinusoids at varying frequencies is used to obtain the spectral responses, with feedback control implemented to ensure consistent amplitudes independent of the plenum’s own dynamics. This discrete calibration technique is shown to significantly reduce uncertainty propagation compared to white noise, chirp or step functions. The effectiveness of the dynamic calibration is validated against laser diagnostics in turbulent flow. As a demonstration of the capability of this technique, spatially-resolved surface pressure statistics are then presented for the five wetted faces of a cube in an atmospheric wind tunnel turbulent boundary layer.