Dynamic response analysis of polyoxymethylene hydrofoils using the hybrid pitch mode FSI method

Abstract

In this paper, the objective is to analyze the dynamic responses of 2D pitching polyoxymethylene (POM) hydrofoils in the uniform flow using the hybrid coupling Fluid-Structure Interaction (FSI) method, which takes account of added mass effects and show its robustness by comparing with the experiments. First, FSI analysis using the empirical formula of hydrodynamic forces around hydrofoils was performed and validated by comparing the analysis results of the weak coupling FSI method and the hybrid coupling FSI method with the analytic solution. Next, The FSI method with Computational Fluid Dynamics (CFD) was implemented in the framework of OpenFOAM, the open-source CFD code. Flow analysis and structural analysis were performed for every time step in the calculations. Here, the flow analysis was performed using Large Eddy Simulation (LES) scheme and the structural analysis was performed by solving the equation which considered the pitch mode of deformable hydrofoils. Dynamic responses of 2D NACA0015 POM hydrofoils using the hybrid coupling FSI method well matched with the experimental results qualitatively, where dynamic responses without the hybrid coupling FSI method showed numerical instability. It is shown that the hybrid coupling FSI method considering added mass effects should be considered for analysis of deformable hydrofoils.