Fluid-structure interactions of a round parachute: Modeling and simulation techniques

A parallel computational technique is presented for carrying out three-dimensional simulations of parachute fluid-structure interactions, and this technique is applied to simulations of airdrop performance and control phenomena in terminal descent. The technique uses a stabilized space-time formulation of the time-dependent, three-dimensional Navier-Stokes equations of incompressible flows for the fluid dynamics part. Turbulent features of the flow are accounted for by using a zero-equation turbulence model. A finite element formulation derived from the principle of virtual work is used for the parachute structural dynamics. The parachute is represented as a cable-membrane tension structure. Coupling of the fluid dynamics with the structural 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 accomplished with an automatic mesh-moving method. The parachute used in the application presented here is a standard U.S. Army personnel parachute.