The interaction between fluid and structural dynamics has become an important topic with regards to understanding the overall dynamics of inflatable aerodynamic decelerators. The present work aims to establish the capability to perform loosely coupled, fluid-structure interactions (FSI) through the use of the Cartesian Navier-Stokes solver, NASCART-GT and the finite element analysis (FEA) tool, LS-DYNA. Verification and validations are presented for the computational fluid dynamics (CFD) in order to demonstrate sufficient accuracy and applicability. These include CFD simulations of moving geometries, as well as a stationary analysis of a rigid tension cone. The FSI capability is demonstrated by examining the flow over a wedge with a deformable membrane, as well as flow over a semi-rigid tension cone configuration. Nomenclature c p pressure coefficient E modulus of elasticity, GPa h material thickness, m M Mach number p pressure, Pa t time, s w wall velocity, m/s x Cartesian coordinate, m y Cartesian coordinate, m z Cartesian coordinate, m α angle of attack, deg ν Poisson ratio ρ density, kg/m 3 () ∞ freestream property

The computational simulation of unsteady Fluid-Structure Interaction (FSI) problems continues to pose many challenges to the computational community. Of the many fundamental elements to partitioned FSI approaches, the most challenging aspects include the treatment of moving components within a fluid dynamics simulation, the consistent and stable transfer of loads between solvers, and the lack of automation in the process. The majority of this paper addresses the first of these problems by presenting simulations of prescribed relative motion through stationary, unstructured Cartesian meshes. Numerical accuracy is investigated through comparisons of moving body simulations to stationary simulations. It is shown that the numerical error increases with moving body simulations, as a result of an increase in wave speed with respect to the mesh. The second FSI component is investigated by considering the partitioned coupling of a 1-D elastic piston, as well as the vortex-induced vibrations of an elastic cylinder in laminar flow. The coupling scheme is analyzed by considering numerical accuracy, stability, and numerical dissipation. The simulations demonstrate accurate predictions in both the response frequencies and the trajectories.

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