Tests of the ONERA Calibration Models in Three Transonic Wind Tunnels

Abstract : A cooperative effort between the Office National d'Etudes et de Recherches Aerospatiales (ONERA); the National Aeronautic and Space Administration, Ames Research Center (NASA-ARC); and the Arnold Engineering Development Center (AEDC) was accomplished whereby two ONERA standard calibration models (M3 and M5) and an area equivalent body of revolution (C5) were tested in the NASA-ARC 11-ft and the AEDC 16-ft and 4-ft transonic wind tunnels. The tests were designed to provide an experimental data base for (1) the evaluation of theoretical or empirical wall-interference correction factors and (2) the establishment of guidelines to allow reasonable selection of wind tunnel to model size ratios in the transonic speed regime. The results showed that large effects of Reynolds number, tunnel flow quality, and small difference in model geometry preclude a determination of wall interference from the M3 and M5 model data. The primary cause of the data differences is a variation in the wing shock/separation patterns between the three tunnel tests. Even though the model forces may, in certain instances, agree from tunnel to tunnel, pressure distributions showed the agreement to be fortuituous. The C5 model data indicated subsonic theory underpredicts the required blockage correction by a factor of two to ten and, because the blockage interference effect changes sign along the model, simply correcting the Mach number will not compensate for the transonic interference.