循环控制无缝隙高升力系统的实验研究
When air is blown from a slot directly upstream of a flap, the flow over the flap can bear large adversepressure gradients without separation. This effect is used to design high-lift airfoils with low momentumcoefficients of blowing. For experimental assessment of these airfoils a rectangular wing with an aspectratio of 4.3 was built. The flow around the model in a low speed wind tunnel is analysed using pressuremeasurements and long distance microscopic particle image velocimetry. To measure the velocity in thevicinity of the slot and next to the surface of the flap the jet is seeded with particles. For Reynoldsnumbers of about Re = 1 · 106 the dimensionless momentum coefficient of the jet and the angle of attackof the airfoil are varied. Numerical simulations of the three-dimensional flow around the circulationcontrol airfoil in the wind tunnel are compared to the experimental data. Good agreement is observedin terms of pressure distributions and velocity profiles.