ASYMPTOTIC METHODS FOR THE PREDICTION OF TRANSONIC WIND-TUNNEL WALL INTERFERENCE

Two limiting cases related to transonic wind-tunnel wall interference are considered. The first concerning slender airplanes is briefly trea ted only as it pertains to the main discussion relating to high aspect ratio configurations. Principal features of the slender airplane case are a three-deck flow structure as well as an area rule for interfere nce. Pressure-specified wall conditions are incorporated by addition o f averages and Fourier transforms of the wall pressures that modify th e far field that controls the interference. For a high aspect ratio tw o-deck second case, the interference is driven by the imaging in the T refftz plane projection of the experimental pressure-specified control surface of the (outer deck) trailing vortex system in the Trefftz pla ne. This gives a downwash correction to a near-field nonlinear lifting line (inner deck) flow. Slightly subsonic freestream conditions give a spikelike interference flowfield due to the interference-induced sho ck movement for both limiting cases. Approaches integrating the asympt otics with measurement to augment wall interference assessment/correct ion procedures are outlined.