Subsonic wall interference corrections for half-model tests using sparse wall pressure data

Subsonic wall interference corrections for half-model tests using sparse wall pressure data

Mokry, M.

National Research Council Canada, National Aeronautical Establishment, High Speed Aerodynamics Laboratory

1985-11-30

A method is described for correcting subsonic wind tunnel measurements on halfmodels in ventilated test sections, operated at subcritical flow conditions at the walls. For perforated walls, the boundary values of the streamwise component of the wall interference velocity are obtained from static pressures measured by a few longitudinal pressure tubes or rails attached to the walls and from the estimated farfield of the model in free air. The sparse boundary data is extended by means of streamwise smoothing and transverse interpolation. The streamwise velocity correction is derived from the doublet panel solution of an interior Dirichlet problem and the transverse corrections by integrating the irrotational flow conditions. The evaluated corrections to Mach number and angle of attack, presented as contour plots in the wing plane, provide insight into the correctability of the test results. Examples are given for a transport aircraft half-model tested in the N AE high speed wind tunnel. Applicability of the method at supercritical flow conditions at the model is examined on experiment al and computational data of a high aspect ratio wing in the Lockheed CFWT facility.

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National Research Council Canada

Campus only

National Research Council Aeronautical Report LR 616; NRC No. 25132

Aerospace Engineering Reports

report

(c) 1985 National Research Council Canada