Micro-Jet Control of Flow in NACA 4412 Wing

Abstract

The separation and coherent structures resulting from the fluid detachment and the presence of marginal wing vortices lead to a decline in aerodynamic performance, noise generation, and vibrations. To address these issues, boundary layer control through blowing via micro-jets proves to be a highly effective solution, as it allows for a significant input of momentum near the wall. An experimental study, based on continuous tangential blowing through a series of micro-orifices, was conducted in a wind tunnel to analyze the effect on the flow over the upper surface of a NACA 4412 wing. Force measurements were taken for various velocities and angles of incidence. Wall and wake pressure measurements also carried out. The results obtained indicate that the blowing effect depends on the location of the blowing orifices and the ejected air flow rate. The analysis of drag and pressure mappings in the wake reveals that blowing near the wingtip generally leads to the generation of a more intense trailing vortex, causing the production of parasitic drag. Furthermore, lift results show a maximum relative gain of 37% at a Reynolds number of 1.6×105 , accompanied by a 2-degree delay in stall.