Numerical simulation of the free surface flow passing two hydrofoils

Abstract

In this paper, a numerical method based on potential flow theory is proposed to investigate the hydrodynamic interaction between two foils with free surface effect. The integral equation is solved using boundary element method. On foil surfaces, the impermeable boundary condition is satisfied. On free surface, nonlinear kinematic and dynamic boundary conditions are satisfied. A robust numerical model is proposed to avoid the complicated vortical interference between the two foils. A fully nonlinear scheme is developed for the numerical simulation. The proposed method is validated by extensive convergence studies. The hydrodynamic loadings on the foils are investigated in time domain. Two major quantitative findings are discussed. Firstly, the free surface elevation could be weakened significantly if the two foils are appropriately arranged. Secondly, the lifting force of the following foil varies periodically with the increase of the horizontal distance between the foils.