Hydro-elastic analysis of flexible marine propellers

Higher efficiencies, higher cavitation inception speeds and reduced acoustic signature are claimed benefits of flexible composite propellers. Analysing the hydrodynamic performance of these flexible propellers, implies that a coupled fluid-structure interaction (FSI) computation has to be performed. An FSI coupling can be monolithic, which means the equations for the fluid and structural sub-problem are merged into one set of equations and solved simultaneously. Another approach is to apply a partitioned coupling, in which the existing fluid and structural sub-problem are sequentially solved. Then, coupling iterations are performed to converge to the monolithic solution. When coupling iterations are omitted, the approach becomes a so-called loose coupling. Due to the relatively high fluid added mass, flexible propeller computations require a strong coupling including coupling iterations. Coupling iterations make these kind of computations CPU intensive and therefore it is of importance to solve the structural and fluid problem efficiently.