Reduction of Spanwise Flow Over a Swept Wing using an Air Curtain Produced by Rectangular Slot

Although swept-back wings improve aircraft performance at high speeds by delaying the shock waves and accompanying wave drag rise, they suffer from wingtip stalls during take-off and landing due to spanwise flow decreasing the effective flow velocity near the wingtip. Flat plates (boundary-layer fences and wing fences) were attached to the upper surface of the aircraft wing parallel to the freestream to obstruct the spanwise flow and prevent the entire wing from stalling at low-speed flights. We propose to replace the wing fences by injecting flow from fluidic actuators vertically into the wing boundary layer to block the spanwise flow. We investigated the concept using a single slot placed at 45% span of the main wing and observed the effect on force and moment coefficients. Numerical simulations are carried out on the NASA Trap Wing Configuration-1 with no brackets in STAR CCM+ by solving steady Reynolds-Averaged Navier-Stokes (RANS) equations and the SST k-w model for turbulent modeling. We performed a mesh study and calculated the lift and drag coefficients over a range of the angle of attacks. After comparing the results against experimental measurements, we found a good agreement. Furthermore, simulations confirmed the spanwise flow at a high angle of attack operation.