Fluid-structure interactions of a round parachute: Modeling and simulationtechniques

A parallel computational technique is presented for carrying out three-dime nsional simulations of parachute fluid-structure interactions, and this tec hnique is applied to simulations of airdrop performance and control phenome na in terminal descent. The technique uses a stabilized space-time formulat ion of the time-dependent, three-dimensional Navier-Stokes equations of inc ompressible flows for the fluid dynamics part. Turbulent features of the fl ow are accounted for by using a zero-equation turbulence model. A finite el ement formulation derived from the principle of virtual work is used for th e parachute structural dynamics. The parachute is represented as a cable-me mbrane tension structure. Coupling of the fluid dynamics with the structura l dynamics is implemented over the fluid-structure interface, which is the parachute canopy surface. Large deformations of the structure require that the fluid dynamics mesh is updated at every time step, and this is accompli shed with an automatic mesh-moving method. The parachute used in the applic ation presented here is a standard U.S. Army personnel parachute.