Development of a hydrofoil wake oscillator model based on a near-vortex strength for predicting vortex-induced vibration on a hydrofoil

Recently, the evaluation of vortex-induced vibration has emerged as a significantly important issue owing to the development of high-speed and lightweight ships and submarines. To derive an accurate vortex-induced vibration response, it is essential to consider the fluid-structure interaction. Moreover, it is necessary to evaluate the generation of the fluid-structure interaction to effectively prevent catastrophic failure in the structures. In this study, a hydrofoil wake oscillator model was developed based on a near-vortex strength that considers the fluid-structure interaction. The near-vortex strength was calculated from the boundary layer on a trailing edge to overcome the empirical parameter of lift fluctuation in conventional wake oscillator models. To predict the vortex-induced vibration on a hydrofoil, procedures for calculating the near-vortex strength and coupling the structural equations and fluid equation were introduced. The vortex-induced vibration derived using the developed hydrofoil wake oscillator model was verified by comparison it against the experimental results. The results reveal that the derived amplitude and lock-in range of the vortex-induced vibration were consistent with the experimental results. In addition, the extent of occurrence of the fluid-structure interaction and its contribution to vortex-induced vibration were evaluated using a non-dimensional wake parameter.