Numéro : 2816 - Year : 2025
Investigation des modes propres d'une helice marine Investigation of the structural acoustic
Mahrez AIT-MOHAMMED, Alexandre BACCOUCHE - DGA TH – Division Essais et Simulations – Val de Reuil (France)
Modal analysis is the most fundamental investigation when dealing with the dynamic behaviour of a mechanical system. However, it is a fact that numerically estimating the natural frequencies of a structure rotating in a viscous and heavy fluid is quite challenging due to the inertia effect. A structural-acoustic coupling is employed to assess the free vibration behaviour of a marine propeller. The method based on the fluid-structure interaction (FSI) technique is investigated using both Abaqus and Actran solvers in which water is represented using an acoustic domain.
Simulation results show a significant reduction in the natural frequencies with respect to frequencies in the air due to the added mass effect closely linked to the water induced inertia. The reductions in the natural frequencies predicted by Abaqus are approximately 56% for the first bending modes, 32% for the second bending modes, and 38% for the torsional mode. A similar reduction in natural frequencies was obtained using the Actran solver. It was concluded that the natural frequency of the propeller decreases when the propeller is placed in water for the same boundary conditions and the added mass is computed using a frequency reduction ratio and the propeller mass.
This paper is written in English
Advanced search
Year