UBC Theses and Dissertations
A new slotted-wall method for producing low boundary corrections in two-dimensional airfoil testing Williams, Christopher Dwight
This thesis deals with a new approach to reducing windtunnel wall corrections in airfoil testing, by employing a transversely-slotted wall opposite the suction side of the airfoil, and a solid wall opposite the pressure side. The solid elements of the slotted wail are symmetrical airfoils at zero incidence. This geometry permits the flow to assume closely the streamline pattern for unconfined flow, without degrading the flow quality through shear layer mixing near the test airfoil. The theory uses the potential flow surface source-element method, with Kutta conditions satisfied on the test airfoil and the wall slats. In experiments using a range of sizes of airfoils of three different profiles, good agreement with the predictions of the theory has been obtained. It appears that uncorrected lift coefficients and pressure distributions, accurate to within one percent, can be obtained for a wide range of airfoil shapes, sizes, and lift coefficients, using a slotted wall of open-area ratio between 60 and 70 percent.
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