Effect of Tangential Blowing on Two Dimensional Boundary Layer of a Wind Tunnel

Abstract

This paper reports an experimental effort to investigate the influence high-pressure air jet on the boundary-layer of the research low–speed wind tunnel of the Instituto Tecnologico de Aeronautica (ITA). Boundary layer control is very important in two-dimensional airfoil model tests. This may be done by either suction or blowing of the boundary layer. At ITA it was decided to blow high energy air into the test section. The literature reports that tunnel wall boundary-layer control, at the wall-model junctions, is necessary in order to obtain useful results from two-dimensional high-lift tests in wind tunnels. Here, it is shown results of the interaction of several configurations of the air jet with the wind tunnel boundary layer. Three injector thicknesses were used 1.0 mm, 1.5 mm and 2.0 mm. The angle was either of 10 o or 20 o . Boundary layer measurements were obtained using a pressure rake. It was positioned at eight stations along the test section, X1=10 cm, X2=16 cm, X3 =22 cm, X4= 28 cm, X5= 34 cm, X6= 40 cm, X7= 50 cm e X8= 60 cm measured from blower slot. The free stream dynamic pressure was kept constant, q∞ = 325 mmH2O.