Numerical simulation of parafoil inflation via a Robin–Neumann transmission-based approach

In this paper, a partitioned coupled iterative approach based on the Robin–Neumann transmission condition is proposed for the fluid–structure interaction simulation of the inflation process of a parafoil. The Reynold-averaged Navier–Stokes equations and the versatile finite element method are employed to solve the fluid flow field and the structural deformation, respectively. The generalized-α time integration scheme for the structure and the second order back Euler scheme for the fluid are incorporated in the Robin-Neumann method. A modified spring-transfinite interpolation hybrid method is exploited to detect the deformation of the grid and regenerate the grid for the fluid architecture. Both a two-dimensional case and a three-dimensional case are studied to examine the feasibility of the present approach. The simulation results reveal the evolution of the flow regime during the inflation process when the air pours into the parafoil. The whole inflation process can be concluded as two stages: the span-wise deployment and the longitudinal expansion. The numerical aerodynamic performance agrees well with that obtained by wind-tunnel experiment, suggesting the effectiveness of this method in handling such a highly nonlinear fluid–structure interaction in parachute inflation.