احمدرضا کهنسال

Amphibious vehicle with different uses, unlike ordinary marine vessels, can enter or leave the sea without any port facility, anywhere in the coast. In this thesis, numerical analysis of amphibious vehicle in a calm water by numerical method has been studied. For this purpose, the RANS equations with the k-? disturbances model were used to simulate the flow around the amphibious vehicle hull. Free surface of flow was modeled by a two-phase fluid volume(VOF) model. Initially, a planing boat was modeled and analyzed by using this method, and numerical results were compared with experimental results. In the next step, three hull with different rise angle were compared and the body that showed the best hydrodynamic properties was selected.Then split submerged type hydrofoil with convensional arrangement was installed on the selected hull and analyzed. The analyzise results of both selected amphibious with and without hydrofoil were compared. The results of the comparison, showed the reduction of resistance, decrease in the wetted surface and the lifting force increase of amphibious with hydrofoil. To validation in all amphibious vehicles a comparison was carried out between the numerical results obtained from this method and the results obtained from semi-experimental relationships provided by Savitsky.This comparison showed a good correlation between the results of these two methods. Another purpose of the study is the design of a dual-mode propulsion system that uses only one engine to provide propulsion in two modes of movement in water and land. Using the results of this study, in addition to the localization of the knowledge of the construction of such vehicles, the amphibious vehicle speed can also be increased by reducing the number of engines to one engine. Also, by installing the hydrofoil on the hull, we will see a decrease in the wet surface and increase the speed due to the lifting force produced by the hydrofoil.