Keywords: parallel, simulation, fluid-structure interaction.

In the past twenty years the design procedure for cable-membrane structures has not changed significantly. To enhance the design procedure for these structures a more accurate analysis is required in relation to wind and snow. Furthermore, it has also become increasingly important to study the internal environments of large covered areas which are enclosed by a membrane structure. For example, the investigation of ventilation schemes and fire safety features are essential. In this paper, research is outlined which is directed towards solving the above described problems as a fluid-structure interaction problem. Although air is a gas and compressible, but since wind speed is significantly lower than the speed of sound in air, it can be assumed that the modelled wind is incompressible. The general governing equations for fluid are therefore the incompressible Navier-Stokes equations. These equations are discretised using the finite volume method which utilises the integral form of the conservation equations (space, mass and momentum conservation). The staggered or partitioned method [1] is used to couple the fluid and the structure into an interaction problem. Farhat et al. [2] suggested a three field system, where the fluid, the structure and the underlying fluid mesh are handled as independent systems. In this case each system can be solved with a well established method for the particular problem. Furthermore the parallelisation of the individual components is also easier than that of the complex system. One of the difficulties with the interaction problem is that the shape of the structure changes and the underlying meshes must follow these changes and keep the geometry consistent. Thus, without a mesh modification strategy the mesh would become distorted and finally invalid. This paper discusses a method which uses the spring analogy [3]. For cases where the deformations are large and the mesh quality deteriorates with time, a local remeshing method is implemented, in which the distorted elements are removed and these parts of the mesh are regenerated. The paper discusses the details of the parallel implementation of the fluid solver and the parallel mesh modification scheme. The remeshing method is divided into a parallel element selection and a sequential meshing step. The parallelised method has been validated with a benchmark problem and finally a fluid-structure interaction problem is presented. The results are compared with the solution published by others [4]. Good agreement is found between the current calculations and the published results.

1

K.C. Park, C.A. Felippa, "Partitioned analysis of coupled system", in T. Belytschko, T.J.R. Hughes, (editors), "Computational Methods for Transient Analysis", volume 1, Computational Methods in Mechanics, Chapter 3, pages 157-219, Elsevier Science Publishers B.V., 1983.

2

C. Farhat, M. Lesoinne, N. Maman, "Mixed explicit/implicit time integration of coupled aeroelastic problems: three-field formulation, geometric conservation and distributed solution", International Journal for Numerical Methods in Fluids, 21:807-835, 1995. doi:10.1002/fld.1650211004

3

J.T. Batina, "Unsteady Euler airfoil solutions using unstructured dynamic meshes", AIAA Journal, 28(8):1381-1388, 1990. doi:10.2514/3.25229

4

M.P. Rast, "Simultaneous solution of the Navier-Stokes and elastic membrane equations by a finite element method", International Journal for Numerical Methods in Fluids, 19(12):1115-1135, 1994. doi:10.1002/fld.1650191205

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