Objectives  Stern flaps have a significant impact on the water performance of high-speed amphibious platforms. This paper discusses the influence of stern flaps on the motion and hydrodynamic characteristics of a high-speed amphibious platform in a sliding state.

  Method  Using the SST k-ω turbulence model and overset grid technology, the CFD numerical simulations of an amphibious platform's high-speed navigation under static water conditions are performed, and the motion response and stability of the platform with different stern flaps are analyzed. Considering the influence of the velocity, center of gravity and angle of the stern flaps on the longitudinal motion of the platform, supporting vector machines are adopted to classify and recognize the boundary of its motion stability.

  Results  The results show that the stern flaps reduce the sailing trim angle by changing the pressure distribution on the underside of the platform, and the larger the rotation angle of the stern flaps, the more significant the influence on motion stability; when the position of the center of gravity is the same, the maximum speed of the platform in a stable state is increased.

  Conclusion  The application of stern flaps and the improvement of motion stability are of great significance for the development of high-speed amphibious platforms.