A corotational finite element approach coupled to a discrete forcing method to solve hyperelastic deformation induced by two-phase flow

Fluid–structure interaction is an ever occurring phenomenon in engineering. In power plants for instance, fuel rods, tubes in steam generator or cooling towers may deform under the extreme load caused by the fluid flowing around them. It may also be valuable to study this kind of interaction during pipelines installation or for wind generating structures. If the deformation is sufficiently important as to influence the fluid behaviour, the problem must be tackled as a whole. Therefore, fluids and structures cannot be processed separately. In this work, a fluid–structure interaction method taking into account the large deformation of simple geometry is developed in neptune_cfd, a 3D multiphase flow code based on Eulerian–Eulerian approach with a single pressure. The solid structures are geometrically non-linear elastic beams in plane strain. The coupling interface is tracked with a discrete forcing method based on a time and space dependent porosity method. The latter is updated several times for each time steps in order to ensure convergence. The present formulation is checked on a semi-analytical problem and validated for a dam break over a flexible plate with experimental confrontation and comparison.