A comparative study of BGK (Bauer Garabedian Korn) No. one airfoil data in the NAL (Japan) and IAR (Institute for Aerospace Research, Canada) high Reynolds number transonic wind tunnels was performed to evaluate the techniques and the accuracy of airfoil testing. Tests were conducted from a low subsonic speed over the design speed of the airfoil mainly at a Reynolds number of 21 million based on airfoil chord at both facilities. Pressure distributions and aerodynamic characteristics measured in both wind tunnels are compared and discussed. The results of the comparisons reveal slight differences in shock position and suction peak level ahead of the shock, suggesting the necessity of a correction for sidewall boundary-layer effects. Application of sidewall interference correction to both sets of wind tunnel data improves agreement between the two sets of data. The results also raise new issues on drag measurement and flow two dimensionality at a high angle of attack and/or a high Mach number. The results of this study will lead to improvements in the accuracy of airfoil testing.
A comparative study of BGK No.1 airfoil data in high Reynolds number transonic wind tunnels
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