Investigation of Keel Curvature Effect on the Hydrodynamic Characteristics of a V-Shaped Planing Surface

In this paper, three-dimensional two phase turbulent free surface flow is solved by an in-house code. The incompressible Reynolds average Navier-Stocks equations (RANS) with k-ε turbulence model are solved by the finite volume method in the non-orthogonal curvilinear coordinates. For the modeling of the free surface effect, Lagrangian propagation volume tracking method (VOF-PLIC) is used. The code is validated solving two-phase turbulent flow through the impact problem of a circular cylinder. Then, the horizontal movement of a NACA standard wedge with 20 degree deadrise angle is simulated. The flow field and generated waves is estimated with different velocities. Numerical results of the average wetted lengths show acceptable compatibilities with the available experimental data. In addition, some modifications on the V-bottom are done to investigate the effect of the keel curvature and deadrise angle on the hydrodynamic forces. In each cases the ratio of the lift and drag coefficient to the conventional wedge with 20 degree deadrise angle is evaluated. It is depicted that the convex curvature doubles the drag coefficient and has not any significant effect on the lift coefficient. The results confirm that the deadrise angle reduction decreases the needed engine power in take-off. However, this reduction has a destructive effect at the time of landing.