TIP FLOWFIELD OF A LOW ASPECT RATIO CIRCULATION CONTROL WING WITH SPANWISE VARIATION IN EFFLUX

A stereoscopic particle image velocimetry (SPIV) system was used in a low-speed wind tunnel to measure the external flowfield of a circulation control (CC) wing having an aspect ratio of 1.1. This ongoing project, sponsored by the Office of Naval Research, sought to further the knowledge of the jet interactions and the wingtip vortex formation through 3-component, planar velocity surveys. The CC wing tested had a 20% elliptic airfoil section with a trailing edge Coanda surface that was intended to increase circulation control effectiveness throUgh a segmented system that could create spanwise massflow efflux profiles. To date, 1.2 TB of raw SPIV data have been acquired in one of two wake station planes at z/c = 1.25 over the vertical region of 0.13. < y/b < 0.87 (i.e, the tip region). The three-component velocity data revealed the nature of the interaction of the jet with the external flowfield and the temporal variability at an overall momentum coefficient of 0.08 with spanwise variations in the trailing edge efflux. The results from these tests will be used to quantify, for the first time, the effects of spanwise massflow distributions on the 3D velocity field near the trailing edge, the stall modes, jet interactions, and the overall performance of a CC wing of this geometry