AN EXPERIMENTAL-STUDY OF A TURBULENT WING-BODY JUNCTION AND WAKE FLOW

Extensive measurements were conducted in an incompressible turbulent f low around the wing-body junction formed by a 3:2 semi-elliptic nose/N ACA 0020 tail section and a flat plate. Mean and fluctuating velocity measurements were performed adjacent to the wing and up to 11.56 chord lengths downstream. The appendage far wake region was subjected to an adverse pressure gradient. The authors' results show that the charact eristic horseshoe vortex flow structure is elliptically shaped, with p artial-derivative (W)/partial-derivative Y forming the primary compone nt of the streamwise vorticity. The streamwise development of the flow distortions and vorticity distributions is highly dependent on the ge ometry-induced pressure gradients and resulting flow skewing direction s. The primary goal of this research was to determine the effects of t he approach boundary layer characteristics on the junction flow. To ac complish this goal, the authors' results were compared to several othe r junction flow data sets obtained using the same body shape. The trai ling vortex leg flow structure was found to scale on T. A parameter kn own as the momentum deficit factor (MDF = (Re(T))2 (theta/T)) was foun d to correlate the observed trends in mean flow distortion magnitudes and vorticity distribution. Changes in delta/T were seen to affect the distribution of u', with lower ratios producing well defined local tu rbulence maxima. Increased thinning of the boundary layer near the app endage was also observed for small values of delta/T.