Experimental investigation of the effect of hydrofoils position on hydrodynamic resistance of the gliding hydrofoil craft

AbstractHydrofoil craft has submerged wings that mounted with struts below of the hull. With the onset of movement and the production of lift by hydrofoils, the craft hull is separated from the water surface, thereby reducing its resistance and increasing its velocity. The position of the hydrofoils along the body have a significant effect on the resistance, hydrodynamic performance and stability. In this paper, are investigated influence of longitudinal position of front hydrofoil on the hydrodynamic resistance of a hydrofoil craft in three modes and at six different speeds through ship model test. Experiments have been carried out in a towing tank of NIMALA. The results showed that the total resistance coefficient curves showed similar physical behavior between 0.27 to 1.64 in all three states. in this range, the lift created by the front and rear hydrofoils of the model causes the body to be uniformly separated from the water surface and to reduce friction resistance, that in general comparison of these situations, the position of the front hydrofoil at a distance of 56 cm from the center of gravity of the model(Position-1) due to the proper distance of the two front and rear hydrofoils relative to the center of gravity and also to each other has less resistance.