Representation and Application of Uncertainties at a Hypersonic Wind Tunnel

Abstract

To estimate uncertainties of wind tunnel test data, it is necessary to analyze statistical uncertainties of tunnel flow conditions. The tunnel flow field should be calibrated at many points in time and space. At a blow-down type hypersonic wind tunnel, this multipoint calibration of the flow field has to be divided in many tests. Among these many tests, random error limits estimated from statistical assessments of Mach number measurements were applied to judge the measurement repeatabilities including liquefaction free flow. The uncertainties of the flow conditions were validated through comparisons of standard model test data in/out of two calibration ranges across the years. Methodology to represent hypersonic wind tunnel performances has been established for data quality assurances by applying the statistical uncertainty assessments.