Periodic dual-mixing method for fast and robust solving of ultra-thin fluid-structure interaction problems

This study proposes the periodic dual-mixing method (PDMM) that can rapidly and robustly solve ultra-thin fluid-structure interaction (UTFSI) problems, especially in severe mixed lubrication. The dual mixing denotes a two-step process: the first step is to mix the historical inputs and outputs separately according to optimal mixing weights; the obtained results are mixed with dynamic damping factors in the second step to predict the deformation of the next iteration. Meanwhile, the residual is injected into the predicted deformation periodically. The comparison study is carried out with the popular IQN-ILS method in general FSI, which shows the PDMM is 5.3 times faster and 5 times more robust. Furthermore, the advantages of the PDMM are more significant under harsh mixed lubrication conditions.