EFFECT OF THE TUNNEL-WALL BOUNDARY LAYER ON TEST RESULTS OF A WING PROTRUDING FROM A TUNNEL WALL

摘要

Two-dimensional span-loading tests were made of a two-foot-chord NACA 651-012 airfoil model in the 2 1/2-foot by 6-foot test section of the Langley stability tunnel to determine tunnel-wall boundary-layer effects. The tests indicated that a small loss (less than one percent of the load at the center) in average load may be expected. At the tunnel wall the load may be as much as 10 percent lower than that at the center of the tunnel, and large changes in the tunnel-wall boundary-layer thickness produce small changes in load. At low angles of attack the tunnel-wall boundary layer had little effect on the pitching moment. At high angles of attack, the average pitching moment for the wing may differ from the pitching moment at the center of the tunnel because of nonuniform stall.