Numerical simulation of marine propulsors hydrodynamic behaviour

Abstract

A numerical method is developed to assess the vibrations on rudder and pod strut due to the propeller action. The method involves both potential and RANSE (Reynolds-Averaged Navier-Stokes Equations) solvers. In unsteady state mode, amplitudes of fluctuations of hydrodynamic forces on the rudder or on the pod strut operating in the propeller slipstream are far from negligible and, depending on the configuration, frequencies of the fluctuations are not only at blade rate (BR) but also at blade rate multiples (BR/sub 4/) and at frequencies comprised between BR and RPM because the propeller is itself operating in an unsteady state mode. It is also shown how sheet cavitation developing on the propeller blades can be taken into account. Finally a finite element code can be used to complete the computation sequence.