We present a parallel computational strategy for carrying out 3-D simulations of parachute¯uid±structure interaction (FSI), and apply this strategy to a round parachute. The strategy uses a stabilized space-time ®nite element formulation for the¯uid dynamics (FD), and a ®nite element formulation derived from the principle of virtual work for the structural dynamics (SD). The¯uid±structure coupling is implemented over compatible surface meshes in the SD and FD meshes. Large deformations of the structure are handled in the FD mesh by using an automatic mesh moving scheme with remeshing as needed. Ó

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One of the major problems in¯uid±structure interaction using the arbitrary Lagrangian Eulerian approach lies in the area of dynamic mesh generation. For accurate¯uid-dynamic computations, meshes must be generated at each time step. The¯uid mesh must be regenerated in the deformed¯uid domain in order to account for the displacements of the elastic body computed by the structural dynamics solver. In the elasticity-based computational dynamic mesh procedure, the¯uid mesh is modeled as a pseudo-elastic solid the deformation of which is based on the displacement boundary conditions, resulting from the solution of the computational structural dynamics problem. This approach has a distinct advantage over other mesh-movement algorithms in that it is a very general, physically based approach that can be applied to both structured and unstructured meshes. The major drawback of the linear elastostatic solver is that it does not guarantee the absence of severe element distortion. This paper describes a novel mesh-movement procedure for mesh quality control of 2-D and 3-D dynamic meshes based on solving a pseudo-nonlinear elastostatic problem. An inexpensive distortion measure for different types of elements is introduced and used for controlling the element shape quality. The mesh-movement procedure is illustrated with several examples (large-displacement and free-boundary problems) that highlight its advantages in terms of performance, mesh quality, and robustness. It is believed that the resulting scheme will result in a more economical simulation of the motion of complex geometry, 3-D elastic bodies immersed in temporally and spatially evolving¯ows. IntroductionAn understanding of the nature of¯uid±structure interaction (FSI) is becoming increasingly important for many kinds of¯ows. Numerous physical phenomena provide examples of¯uid±structure interaction [1, 2] (e.g., induced vibrations of cable suspension bridges, skyscrapers, chimneys, arti®cial heart valve devices, offshore and aeronautical structures). FSI problems require the concurrent application of computational¯uid dynamics (CFD), computational structural dynamics (CSD), and computational mesh dynamics (CMD) techniques.The approach presented here pertains to structures that undergo large displacements and large rotations due tō uid dynamic loads. For such problems, the¯ow ®eld is affected by structural deformations. As a result, the¯uid and structure exhibit a two-way coupling, and it is necessary to resolve the¯ow ®eld after each update of the structural con®guration. The procedure is based on loose coupling of three ®eld problems: the¯ow, the elastic body, and the mesh-movement ± that is, the CFD, CSD, and CMD procedures.We selected the ALE form of the Navier±Stokes equations for the¯uid and the updated Lagrangian formulation for the structure. In problems that involve large displacements, the ALE mesh must be adjusted after each update of the structural con®guration. When the structural displacements are of the same order of magnitude as a characteristic leng...

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