Ahmad Reza Kohansal

In this study, effective geometrical parameters to achieve the optimal hull form of highspeed light craft have been concentrated. First, effect of adding a tunnel on monohull drag force reduction was evaluated. Effect of tunnel height and aperture on hydrodynamics behavior as the most effective parameters were studied to define some performance criteria. The performance assessment of tunnel vessel has also been done parametrically for each of dependent and effective variables separately. Numerical simulation has been done using ANSYS Fluent commercial software. The Simple algorithm was implemented to the relationship between pressure and velocity, VOF method was used to two fluid phases analysis. Also, k - ɛ algorithm was used to simulate turbulence. The numerical simulation has been done through 6DoF. The simulation. findings have been compared to a semi-experimental method, Savitsky. This comparison reveals the simulation's accuracy and a strong agreement with other methods. According to the results, the adding lateral tunnels has a high impact on the drag force reduction to %35 at high speed. The tunnel height and aperture are the most effective parameters of switching vessel to planing mode, also the smaller surface of tunnel, the easier this happens.