The Scale Effect Study on the Transient Fluid–Structure Coupling Performance of Composite Propellers

Abstract

In order to predict the fluid–structure coupling performance of a full-scale composite propeller under a wake flow field behind a full ship, a bidirectional transient fluid–structure coupling algorithm was established. The performance includes the transient fluid–structure coupling deformation, structural natural frequency, and unsteady hydrodynamic performance. The results showed that the circumferential non-uniform wake flow field can cause periodic pulsation of the propeller’s hydrodynamic force. The average values of thrust and torque coefficient increase, while the pulsation ratio decreases with the increase in scale. The maximum deformation ratio of fluid–structure coupling is linearly related to the scale ratio. Due to the influence of fluid-added stiffness, the maximum deformation ratio needs to be modified by 3% based on the cantilever plate deflection formula. The first five natural frequencies of dry mode and wet mode decrease with the increasing scale, and the wet natural frequencies of each order decrease by 60~68% compared with dry mode. The fluid–structure coupling hydrodynamic performance still show a periodic pulsation with the phase angle, and its average value increases linearly with the scale ratio, while the pulsation ratio decreases with the power relationship of the scale ratio.

Keywords

• composite materials
• propeller
• non-uniform wake flow field
• transient fluid–structure coupling
• natural frequency
• scale effect