Abstract

In this study, three well-known approaches for computing mode shapes and natural frequencies of fluid-structure systems are investigated and compared. These techniques are variants of subspace, Lanczos and Arnoldi eigensolvers suitable for considered problem. The fluid and structure domains are discretized with finite elements and are formulated based on pressure and displacement degrees of freedom, respectively. It is well known that the eigenproblem which governs free vibration of such a system has unsymmetric matrices. The accelerated pseudo-symmetric subspace iteration method, which is recently proposed for fluid-structure problems, is the most efficient version of subspace method for this problem. In addition, two-sided Lanczos iteration and implicitly restarted Arnoldi methods are adjusted for fluid-structure problems and compared from efficiency point of view. Several numerical analyses are carried out which lead to the conclusion that Krylov subspace projection methods are more efficient than subspace method. Moreover, implicitly restarted Arnoldi method is the most efficient and stable one among three investigated approaches for mentioned problem.