Hydrodynamic characteristics of a surfing paddle-wheel used in high-speed amphibious vehicles

Conventional amphibious vehicles usually feature a complex propulsion mechanism, low water speed and poor land trafficability, and high energy consumption. To address these concerns, this paper proposes a high-speed propulsion technology suitable for amphibious vehicles and designs a novel paddle-wheel structure by virtue of the theory of high-speed hydrodynamics. In addition, the dynamic characteristics of the surfing paddle-wheel is investigated by using a hydrodynamic approach. The lift force and drag force of the paddle-wheel with different rotation speeds and immersion depths were evaluated. When the paddle-wheel is rotating in water, the relationship among the lift force, rotation speeds and immersion depths of the paddle-wheel was established by using the numerical simulation. The results reveal conclusively that the novel paddle-wheel can drive the relative flow of the water layer when it rotates, producing a considerable upward lifting force, which is positively correlated with immersion depth. The propulsion force decreases with increasing immersion depth, and is negative when the water depth exceeds the wheel centre. As the rotational speed increases, the paddle-wheel is finally lifted out of the water and enters the high-speed surfing state, validating the availability and practicability of the proposed surfing paddle-wheel.