柔性螺旋桨非定常流场及结构动态响应数值计算

To study the unsteady flow field and structural vibration response of flexible propellers, we used the unsteady computational fluid dynamics (CFD)/finite element method (FEM) coupling method to calculate the dynamic characteristics of the isotropic flexible propeller in uniform flow. We then analyzed the relationship between the unsteady fluctuation and the structural vibration response. In this paper, we present the vibration characteristics of the flexible blade and the mechanism of the flow field coupling. The results show that the generation and dissipation of the unsteady vortex greatly influence the fluctuation of the flow field and the flow field load. Compared with the load fluctuation of hydrodynamic pressure, we found the first two-stage wet-mode frequency of the blade to have a greater influence on the structural vibration. Our results show that the thrust fluctuation of the flexible propeller can be regarded as the superposition of the thrust generated by the static-pressure deformation of the rigid propeller and the fluctuation of flow-field pressure of high-order frequency. In contrast, in uniform flow, the high-order frequency aspect is negligible. As such, it is suitable to use the steady-state fluid-solid coupling method to solve for the open-water performance of the flexible propeller.