A drichlet/neumann strongly coupled iterative method for fluid structure interaction of parafoil inflation process

A detailed description of the Drichlet/Neumann iterative method has been presented and the D/N method combined with the Reynold-Averaged Navier-Stokes (RANS) equations for fluid and versatile finite element method for structure has been employed for simulation of Fluid Structure Interaction occurred in the parafoil inflation process. The generalized-α time integration scheme for structure, the first/second order Back Euler for fluid and the zeroth order structural predictor are incorporated into the D/N method and a mathematical analysis of its numerical stability are also performed to determine the choice of relaxation factor. An innovative modified spring-TFI (TransFinite Interpolation) hybrid method is exploited to mesh the fluid architecture and detect the motion of the grids. The simulation results for a two-dimensional uninflated parafoil case show the evolution of the flow regime during the process when the airflow pours into the airfoil, which compared favorably with those measured either in wind-tunnel. And the influence of the fluid time integration scheme, the choice of time step and the solid structure densities on the performance of FSI (fluid structure interaction) calculation is also investigated.