1. Turbulent Flow Measurements in an Idealized Wing/Body Junction
2. Navier-Stokes solutions for transonic flow over a wing mounted in a tunnel
3. Vortex flaps have been introduced as a means to reduce the additional drag. It was postulated that a downward deflection of the leading edge to parallel the freestream direction will redirect the vector of the vortex suction.2The postulation was found in this work to be oversimplified. The deflected flap created cambered profiles of smaller geometrical and effective angles of attack, and transformed the flat delta wing into a cambered wing with a dihedral. The flowfield also became more complicated than that of a flat delta wing, with two additional vortices generated at the flap hinges.3These changes in the flowfield reduced the leading-edge suction, and resulted in both the lift and the drag forces being smaller. However, the aerodynamic efficiency of the wing, defined by the lift/drag ratio, has improved on occasion. This improvement has been the main goal of several works.4"14The aerodynamic coefficients of configurations with vortex flaps were measured experimentally ,3-1517and predicted theoretically,1819Most of these works dealt with very thin wings. Although Rao10reports on the adverse effect of the thickness on the performance of vortex flaps, the current investigation is of delta wings with substantial thickness. This thickness, being more realistic, also made possible the design of an actual hinge geometry, rather than the virtual hinge used in prior experiments, as well as the observation of the effect of the leading-edge shape.
4. Predictions of vortex-lift characteristics by a leading-edge suctionanalogy