Effect of the fair water fin on the hydrodynamic performance of an amphibious vehicle

An amphibious vehicle is a special transportation method that can travel on land and navigate through water. In this work, a numerical study is conducted that is focused on amphibious vehicles with different parameters of fair water fins added to the flow field corresponding to the designed navigation speed via the computational fluid dynamics method. By analyzing the pressure distribution at the bottom of the amphibious vehicle, the flow field distribution of the fair water fin, and the navigation wave surface, the influences of the fair water fin on the vehicle performance in terms of drag reduction, speed increase, and stability enhancement are investigated. The results show that fair water fins can effectively improve the navigation stability of amphibious vehicles and that the improvement effect is optimal when the fair water fin is relatively tall. The study reveals that the resistance of the amphibious vehicle first increases and then decreases as Fr increases, peaking at Fr = 0.88. When Fr increases from 1.33 to 1.47, the resistance of the original amphibious vehicle and the vehicle with the fair water fin parameter Hf = 0 mm increases, whereas the resistance of the other vehicles continues to decrease. At Fr = 1.47, a maximum drag reduction of 5.217 82% is achieved with Hf = 1 mm. Additionally, the sinkage and trim of amphibious vehicles with added fair water fins generally decrease, and they experience a more significant reduction under high-speed conditions.