Uncertainty Analysis of Test Data in the Ames 11-Foot Transonic Wind Tunnel

Boone, Alan; Field, Moffett

doi:10.2514/6.2004-2195

Cited by 2 publications

(7 citation statements)

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“…Flight Center, and also by Ulbrich and Boone (2004) at the NASA Ames wind tunnel, under similar test conditions. The calculated random components of the uncertainties in these freestream parameters and how they compare to the observed measurement variability are similar to those reported at the NASA National Transonic Facility by Walter, Lawrence and Elder (2010).…”

Section: Validationmentioning

confidence: 94%

“…Such methodologies have been implemented already at many wind tunnels in North America including those at the NASA Langley, Marshall, Glenn and Ames Research Centers (Walter, Lawrence and Elder, 2010;Springer, 1999;Stephens et al, 2016;Ulbrich and Boone, 2004).…”

Section: List Of Figuresmentioning

confidence: 99%

“…The calculated uncertainties are reported for Mach number, dynamic pressure and Reynolds number, each as a function of the respective parameter, at different total pressure set points. To conclude, Ulbrich and Boone (2004) emphasize on the importance of obtaining accurate estimates of the elemental uncertainties or the bias and precision limits of the measured variables, expressing that the analysis can be improved once better estimates become available.…”

Section: Review Of the Literaturementioning

confidence: 99%

“…The precision limits and the partial derivatives are combined to obtain the components of the precision uncertainty vector for each result, while the systematic uncertainty vector is obtained using the bias estimates along with the partial derivatives. The square root of the sum of the norm of the two vectors yields the total uncertainty of the result parameter (Ulbrich and Boone, 2004). An uncertainty percentage contribution is also calculated in the algorithm for every error source, as an indicator of its influence on the overall uncertainty.…”

Section: Review Of the Literaturementioning

confidence: 99%

“…At the NASA Ames Research Center 11-foot transonic wind tunnel, Ulbrich and Boone (2004) have developed an algorithm to estimate the uncertainty of the test results based on the Meyn's uncertainty propagation methodology (Meyn, 2000), which is mathematically identical to the TSM technique or that recommended in the AIAA Standard (1999), yet is easier to implement due to its vector formulation. Similar to the TSM approach, the independent variables of the result parameters are identified, and their associated bias and precision errors are obtained from manufacturer specifications, calibrations, and past test experience.…”

Section: Review Of the Literaturementioning

confidence: 99%

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Uncertainty Analysis of Test Data at the NRC 1.5-Meter Trisonic Wind Tunnel

Fakhraei

Weiss

2016

32nd AIAA Aerodynamic Measurement Technology and Ground Testing Conference

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Ainsi, tous les efforts d'amélioration de la qualité des données devraient être concentrés sur la balance de la demi-maquette et les instruments de mesure de pression, afin de réduire leurs incertitudes. Les résultats des analyses ont été validés grâce à une méthode alternative de propagation des erreurs ainsi que par la comparaison des incertitudes aléatoires calculées avec la variabilité observée des paramètres de sortie. Cela étant, des estimations plus détaillées des biais et des erreurs de précision dans les mesures de la balance dynamométrique pourraient être bénéfiques à l'algorithme. Mots-clés: analyse d'incertitudes, soufflerie, aérodynamique UNCERTAINTY ANALYSIS OF TEST DATA AT THE NRC 1.5 METER TRISONIC WIND TUNNEL Samin FAKHRAEI ABSTRACTAn uncertainty analysis algorithm has been developed at the National Research Council of Canada (NRC) 1.5 meter trisonic wind tunnel in Ottawa, Ontario, in order to assess the data quality in the half-model experiments carried out by Bombardier Aerospace. The analysis follows the methodology recommended by the AIAA Standard S-071A-1999 to propagate the systematic and random errors in the measured variables through the complete data reduction routine, in order to calculate the overall uncertainties of the tunnel freestream parameters and the key aerodynamic force and moment coefficients in the form of a 95-percent confidence interval. Detailed breakdowns of the total uncertainties have been obtained to separately investigate the systematic and random components, and to identify the variables that have the largest contribution to the uncertainties. With the implementation of the developed algorithm, the uncertainties of the results are precisely quantified at every measurement point throughout an experiment. Hence, the analysis can be performed over a range of test conditions, aircraft model configurations, and angles of attack. The data of the most recent Bombardier experiments have been used to present the outcomes. The analyses reveal that the freestream properties are achieved with high accuracy at the NRC wind tunnel, as the uncertainties in the freestream Mach number and dynamic pressure are respectively limited to 0.4% and 0.7% of the desired nominal values. The uncertainties in the coefficients of lift and drag vary over the pitch sweep during a test due to the functional dependence on the normal and axial force, as well as the angle of attack. The magnitudes and the component breakdowns of the uncertainties in these coefficients also vary with the tunnel operating condition and from one test article to another. Nevertheless, the force and pressure measurements consistently appear to be the dominant contributors. Hence, any attempts to improve the data quality should focus on the half-model balance and the pressure measurement instruments to reduce their uncertainty. The analysis results have been validated through an alternative error propagation methodology, and also by comparing the calculated random uncertainties to the observed variability in the result par...

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Section: Validationmentioning

confidence: 94%