Fluid structure interaction analysis of a hydrofoil based on fully coupled algorithm

A fully coupled algorithm for modeling of fluid structure interaction in viscous flow around the NACA0009 hydrofoil is presented. The numerical simulations are performed by using the Theodorsen model and the Munch model to investigate the fluid structure interaction and characterize the factors that significantly affect the hydroelastic responses. It is revealed that Theodorsen's approximation of the hydroelastic moment is based on inviscid, potential flow theory and hence it underestimated the hydroelastic responses to some extent. The fluid inertial, damping, and stiffness forces are not negligible compared to their structural counterparts. For the flexible hydrofoil, the fluid inertial and damping forces increase, suggesting that the numerical instability of fluid structure coupling algorithms may lead to a more significant impact on the numerical prediction of the fluid structure interactions. Meanwhile, the structural stiffness dominates the response of the hydrofoil when the external excitation frequency is set to be the non-resonance frequency, while as the external excitation frequency equals to the resonance frequency, the effect of the fluid damping and stiffness is less significant and the structural response of this case is dominated by the fluid and solid inertial effects in addition to the structural stiffness.