Abstract: Breakwater is one of important parts which affect the performance of amphibious vehicle on water. A hydrodynamics model of displacement amphibious vehicle is established to research the influence of breakwater on its hydrodynamics. The hydrodynamics performance of displacement amphibious vehicle is simulated in terms of different shapes and sizes of breakwaters and their positions relative to vehicle body. The effect of breakwater on navigation resistance, lift force and longitudinal pitching moment is analyzed. The research results show that segmented breakwater is better engineering structure in shape, which has the advantages of arc-shaped and flat-plate breakwaters; the increase in width has small influence on resistance and lift force, but the longitudinal pitching moment increases a lot; with the increase in distance between breakwater and vehicle body, the resistance increases, the lift force decreases, and the longitudinal pitching moment increases greatly; with the increase in angle between breakwater and underbody plane, the resistance and lift force have a little change, but the longitudinal pitching moment increases significantly.

Key words: ordnance science and technology, displacement, breakwater, hydrodynamics, navigation stability