Fluid-structure interaction modeling of the US army personnel parachute system

We present a strategy for carrying out 3-D simulations of parachute fluid-structure interaction, and demonstrate the strategy for simulations of airdrop performance and control phenomena in terminal descent. The strategy uses a stabilized space-time formulation of the time-dependent, 3-D Navier-Stokes equations of incompressible flows for the fluid dynamics solution. A finite element formulation derived from the principle of virtual work is used for the parachute structural dynamics. Coupling of the fluid dynamics with the structural dynamics is implemented over the the fluid-structure interface, which is the parachute canopy surface. Large deformations of the structure are handled in the fluid dynamics mesh using an automatic mesh moving scheme. The strategy is demonstrated to simulate the terminal descent behavior of a standard US Army personnel parachute system. Also, preliminary simulations are presented for the response of the parachute to a variety of "riser slips," which can provide the parachute system with limited maneuverability.