Partitioned block-Gauss–Seidel coupling for dynamic fluid–structure interaction

This paper presents a fully coupled three-dimensional solver for the analysis of time-dependent fluid–structure interaction. A partitioned time marching algorithm is employed for the solution of the time-dependent coupled discretised problem, enabling the use of highly developed, robust and well-tested solvers for each field. Conservative transfer of information at the fluid–structure interface is combined with an effective block-Gauss–Seidel iterative scheme to enable implicit coupling of the interacting fields at each time increment. The three-dimensional unsteady incompressible fluid is solved using a powerful implicit dual time stepping technique with explicit multi-stage Runga–Kutta time stepping in pseudo-time and an ALE formulation for moving boundaries. A finite element dynamic analysis of the highly deformable structure is carried out with a numerical strategy combining the implicit Newmark time integration algorithm with a Newton–Raphson second-order optimisation method. Test cases are presented to benchmark the algorithm and to demonstrate the potential applications of this method.