Two way coupled hypersonic fluid structure interaction simulations with Eilmer

Fluid Structure Interactions (FSI), if not managed appropriately are known to have contributed to the loss of several aerospace vehicles. As done for the X-43, FSI can be designed-out by making structures sufficiently rigid and by providing appropriate damping. In hypersonic cruise vehicles, this strategy is not applicable as stringent weight limits and large thermal loads result in structures with reduced stiffness [12]. Thus, the accurate simulation and prediction of FSI are essential to allow for the most effective design. In hypersonics, aeroelastic effects can result in rapid variations in pressure and thermal evolutions. The level of coupling between fluid and structure is typically is strong or two-way, which means that CFD and FEM solvers have to continuously exchange information in terms of nodal forces and displacement in order to produce an accurate solution. In this paper we present details of a fast implementation and first results of a FEM solver in the Eilmer CFD solver. Details are provided on the formulation of the structural solver, the fluid solver to appropriately account for the deforming boundaries, and the coupling approach. The results show that the simulations are in broad agreement with experimental data, but that an off-set exists in response frequency and amplitude. The resulting capability, with its ability to conduct time–accurate FSI simulations is a good tool to further investigate the underlying effects driving hypersonic FSI.