Leading-edge geometry effects on the vortex formation of a diamond-wing configuration

The effects of spanwise-varying leading-edge contours with respect to vortex formation are investigated on a diamond-wing configuration named SAGITTA. At low-speed conditions, three different leading-edge configurations are considered for which the spanwise leading-edge contours can be of a sharp or rounded type. In a combined approach, both numerical computations and experimental investigations are therefore conducted. On the one hand, both steady and unsteady Reynolds-averaged Navierâ€"Stokes equations are applied to compute numerical results for all three different leading-edge configurations. On the other hand, wind-tunnel experiments are performed for the reference configuration to study the overall aerodynamic characteristics. It turns out that the agreement between the numerics and experiment is very good. Depending on the chosen leading-edge contours, the numerical analyses show a different vortex formation on the SAGITTA diamond-wing configuration, which results in diverse flow topologies. Both the flow topologies and the characteristics of the aerodynamic coefficients are discussed in detail for the three analyzed configurations. Due to the 12%relative thickness airfoil, vortex formation takes place only at sharp leadingedge segments, but not for rounded leading-edge contours. Despite diverse flow topologies, however, the resulting effects on global performance regarding lift and pitching-moment characteristics are found to be only small for the regarded configurations.