Investigation of Effective Parameters on the Hydrofoil Performance near the Free Surface of Water

In this study, a numerical method is used to assess the effect of thickness, camber, submergence depth
and flow velocity around a submerged hydrofoil. A pressure based algorithm is used to solve Navierstokes
equations, and Volume of Fluid (VOF) approach is applied to simulate two-phase fluid (water
and air). The model and second order upwind scheme have been used for turbulence models and
differential schemes, respectively. For verifying, a part of results is compared with published
experimental results. The numerical and experimental results show excellent agreement; thus, the
process of numerical simulations is confirmed. The results of this study illustrate that the lift and drag
coefficients increase with rising the thickness of the hydrofoil, but the lift to drag ratio has a
downward trend. On the other hand, the lift and drag coefficients increase with growing the camber of
the hydrofoil, but lift to drag ratio has upward trend. Therefore, to opt the best section of the hydrofoil,
the less thickness and the high camber are more desirable to getting high hydrodynamic performance.
The switched of the hydrofoil section obviously affects the airflow and boundary layer formed on the
free surface of water. Moreover, lift and drag coefficients become high by increasing the submergence
depth and angle of attack, as a result lift to drag ratio increases. Lift and drag coefficients are
decreased by increasing flow velocity, and lift to drag ratio has a downward trend.