CFD-Enhanced Calibration of a Multihole Probe for Small Uncrewed Aircraft Systems

Abstract A robust calibration method with a 9-hole probe (9HP) for inertial wind vector measurements from a small uncrewed aircraft system (sUAS) is presented. Calibration accuracy is improved by using computational fluid dynamics (CFD) to estimate corrections, such as those for test section blockage, that are generally applied in wind tunnel testing. A method for estimating experimental bias is presented to account for flow variations over the pressure taps as the 9HP is repositioned in the test section. Installation effects from flow over the airframe and upwash produced by the wings are estimated from CFD simulations of the entire airframe at the expected cruise speed. An initial CFD analysis has demonstrated a quantifiable linear relationship between the measured and actual angle of attack as measured from the relative wind frame. The objective of these additional steps is to increase the accuracy of 9HP calibration. Significance Statement Multihole probes (MHPs) are flown on small uncrewed aircraft systems (sUAS) to gather precise atmospheric measurements deriving inertial wind. This study demonstrates that MHP calibration accuracy can be enhanced by using computational fluid dynamics (CFD) to characterize the flow field around a probe. CFD analysis can offer corrections to address wind tunnel blockage effects observed during calibration and upwash effects observed during flight.