Three-dimensional topology optimization of a fluid–structure system using body-fitted mesh adaption based on the level-set method

•A parallel framework is built for RDE-based topology optimization.•2D/3D compliance, power dissipation, FSI optimization are presented.•Body-fitted mesh adaptation is used to realize separate modelling.•B-Rep conversion of mesh to CAD is presented.•A complete product development workflow is demonstrated. [Display omitted] We propose a new framework for the two- and three-dimensional topology optimization (TO) of the weakly-coupled fluid–structure system. The proposed design methodology uses a reaction–diffusion equation (RDE) for updating the level-set function based on the topological sensitivity. From the numerical point of view, two key ingredients are highlighted: (i) the body-fitted adaptive mesh strategy allows the disjoint reunion of a global mesh that contains several (fluid/solid) subdomains, whose interfaces can be described by an implicitly defined surface (zero level-set); (ii) our framework uses FreeFEM for finite element analysis (FEA) and PETSc for distributed linear algebra. Efficient preconditioner techniques are utilized to solve the large-scale finite element systems. From the engineering stand point, we propose a complete product development workflow including the pre-processing, TO, B-Rep conversion, and the numerical experiment. The performance of our methodology is demonstrated by solving three different optimization problems: compliance, power dissipation, and fluid–structure interaction (FSI). For comparison and for assessing our various techniques, we benchmark our designs against state-of-the-art works followed by showcasing a variety of practical engineering design examples.