Formation of Leading-Edge Vortex over Flapping Wing Camber using Computational Fluid Dynamic

Leading-edge vortex governs the aerodynamic force production of flapping wing flyers. The primary factor for lift enhancement is the leading-edge vortex (LEV) that allows for stall delay that is associated with unsteady fluid flow and thus generating extra lift during flapping flight. To access the effects of LEV to the aerodynamic performance of flapping wing, the three-dimensional numerical analysis of flow solver (FLUENT) are fully applied to simulate the flow pattern. The effect of the advance ratio to the unsteadiness of the flapping wing will result in the flow regime of unsteady-state (J<1). To access the features of LEV benefits of aerodynamic to the flapping wing, advance ratio of parameter of 0.44 and corresponding to angles of attacks of α = 10o. In this research, the results had shown that in the unsteady state flow, the LEV formation can be indicated during both strokes. The LEV is the main factor to the lift enhancement where it generated the lower suction of negative pressure. For unsteady state, the LEV was formed as expected, the increase in wing camber resulted in a comparable increase in the rotational velocities (downwash velocity). However, it did not result in a major change in the radius of the vortex (LEV). Meanwhile, the non-dimensional circulation increased substantially with increased camber, which was proportional to the increase of LEV radius.