Investigation and comparison of hydrodynamic performance of symmetric and non-symmetric hydrofoils

Various methods are generally applied for drag reduction in vessels which yields the desirable increase in speed. Application of hydrofoil is recognized to be one of the effective methods for reducing the pressure as well as fricitional drag. The aim of the present research is to numerically investigate the hydrodynamic performance of symmetric and nonsymmeteric hydrofoils in three-dimensional form and to compare their performance with the two-dimensioanl results. The result of the current research leads to proper choice for hydrofoil installation on a vessel. The intended simulations are conducted by Ansys-CFX software and RANS equations are solved considering the k-ε turbulent scheme. The numerical result emanationg from the conducted simulations are validated by available experimental data. The targeted computations are performed at various speeds and angles of attack. The obtained results indicate that in different operational conditions, hydrodynamic forces of lift and drag of hydrofoils are different. In all simulation cases, it is observed that lift and drag coefficients of two-dimensional studies are larger than those in three-dimensional studies. However, lift to drag ratio which is considered as the main hydrodynamic performance of hydrofoils, is larger in three-dimensional cases than two-dimensional condition. Furthermore, results indicate that at angle of attack of 1.6 to 2.0 degrees, the lift to drag ration possess a peak of L/D=20.