Evaluation of Wall Interference Effects in a Two-Dimensional Transonic Wind Tunnel by Subsonic Linear Theory

摘要

Results of transonic wind tunnel tests on two-dimensional aerofoils are analysed with respect to the effects of wind tunnel wall interference. The tests were conducted on two geometrically similar models of each of two aerofoil sections - the NACA 0012 and the BGK-1 sections-and covered a range of Mach numbers from 0.5 to 0.82 with model chord to tunnel height ratios of 0.125 and 0.25. Results from measurements on all models in both solid- and slotted-wall test sections are corrected for wind tunnel wall interference effects by the application of classical linearized theory. For the solid wall results, these corrections appear to produce data which are very close to being free of the effects of interference. In the case of slotted walls however, linear theory is found to significantly underestimate the magnitude of blockage interference. The introduction of an empirical blockage correction, when combined with the linear theory representation of lift-interference, enables the cross-flow characteristics of the slotted walls to be determined, and leads to a successful correction scheme for the slotted wall results. Extensive comparisons with data from other sources, both experimental and theoretical, provide further verification that the corrected results are indeed closely interference free. (Author)