Performance of partitioned procedures in fluid–structure interaction

Partitioned simulations of fluid–structure interaction can be solved for the interface’s position with Newton–Raphson iterations but obtaining the exact Jacobian is impossible if the solvers are “black boxes”. It is demonstrated that only an approximate Jacobian is needed, as long as it describes the reaction to certain components of the error on the interface’s position. Based on this insight, a quasi-Newton coupling algorithm with an approximation for the inverse of the Jacobian (IQN-ILS) has been developed and compared with a monolithic solver in previous work. Here, IQN-ILS is compared with other partitioned schemes such as IBQN-LS, Aitken relaxation and Interface-GMRES(R).