Abstract: To study the effects of the arc-anhedral angle, airfoil and leading edge cut of a parafoil on its aerodynamic performance, 3D steady flow field of parafoils with cells, an aspect ratio of 3, and characteristic geometric parameters is numerically simulated by using computational fluid dynamics (CFD) technique. The incompressible Reynolds-average Navier-Stokes (RANS) equations in a 3D coordinate system is solved by using the finite volume method. A k-ω shear stress transport (SST) two-equation turbulent model is also applied to simulate the turbulence. Numerical simulation results of the aerodynamic performance of the original model show good agreement with the tunnel experimental data. The results indicate that the arc-anhedral angle can obviously decrease the lift and induced drag of a parafoil, but the lift-drag ratio changes little. The model with a smaller leading edge radius and thickness of parafoil achieves larger lift-drag ratio. The leading edge cut has little effect on lift and its effect on the flow field is only confined to the region near the leading edge, making the pressure distribution of this model similar to the baseline airfoil. Meanwhile, the leading edge cut decreases the stall angle of attack and obviously increases drag. This paper can provide reference for further studies on parafoil aerodynamic performance with different geometric parameters.

Key words: parafoil, arc-anhedral angle, leading edge cut, aerodynamic performance, numerical simulation, generalized lifting-line theory