Abstract: 3D steady flow fields of parafoils with cells, an aspect ratio of 3.0, and different planform geometries are numerically simulated by using a computational fluid dynamics (CFD) technique to study the planform geometry effect on parafoil aerodynamic performance. The incompressible Reynolds-averaged Navier-Stokes (RANS) equation in a three-dimensional coordinate system is solved by using the finite volume method. The shear stress transport (SST) k-ω 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 elliptical parafoil model achieves the minimal drag coefficient among all the models, because the leading edge cut has changed the flow state, so that its lift coefficient is not the maximum. The swept back leading edge can obviously decrease the drag of a parafoil model. Because the middle part of a parafoil contributes more to effective lift, the model with a swept back leading edge achieves the maximal lift-drag ratio. Drag has a great impact on the lift-drag ratio, and the leading edge cut drag, which has only a two-dimensional effect, is one of the main sources of the total drag. This paper can provide reference for further studies on parafoil aerodynamic performance with different geometric parameters.

Key words: parafoil, planform geometry, aerodynamic performance, numerical simulation, incompressible flow