An Investigation of Three-Dimensional Wall Interference in a Variable Porosity Transonic Wind Tunnel

Abstract : This report presents the results of an experimental program to measure the wall interference effects on an idealized lifting model in the Mach number range from 0.6 to 1.3. The interference phenomena were evaluated by direct comparisons of data obtained in the Propulsion Wind Tunnel (16T) and the Aerodynamic Wind Tunnel (4T) at identical test conditions. The results show how a flow angularity which is apparently a function of model attitude and configuration can be induced into the tunnel flow field and be misconstrued as an upwash interference. The porosity schedule currently used in Tunnel 4T is studied for blockage interference.