Objectives In the flow field, vibration response characteristics of the elastic propeller are influenced by the interaction of the fluid and structure.
Methods Based on the CFD/FEM fluid-structure interaction method, ANSYS-CFX modules on the Workbench platform were applied to simulate the tow-way fluid-structure coupling hydrodynamic performance of the elastic propeller and to analyze the deformation and stress-strain response characteristics of the elastic propeller, and the ACT_Acoustic module was used to compute the wet mode of the elastic propeller taking into account of the influence of fluid-structure interaction on the inherent characteristics. The elastic propeller's spectral analysis was carried out to analyze the response characteristics by the results of the hydrodynamic performance and the wet mode.
Results Compared with the steady uncoupling hydrodynamic results, the fluid-structure coupling hydrodynamic calculations are closer to the open-water test regression formula. The natural frequency of the first fifth order wet mode of the elastic propeller is much lower than the dry modal natural frequency, which decreases by 19%-37%, and the relationship of the fourth and fifth dry-wet modal shapes exchanges. The spectral analysis shows that the hydrodynamic axial thrust and torque are the main influence factors of the structural vibration response in the flow field, and they mainly cause the cantilever vibration of the propeller's first-order wet mode. On one blade, the structural response decreases from the tip to the leading edge and the middle of the blade, and then to the trailing edge, finally to the root.
Conclusions The study in this paper provides an approach to the fluid-structure interaction simulation of the elastic propeller in the flow field, and also lays the foundation for the analysis on the vibration noise of propeller in terms of the fluid-structure interaction.
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