Objectives  The inclined climbing floating characteristics of an unpowered vehicle are analyzed in order to ensure that the floating parameters and water-exit attitude of an unpowered vehicle meet the requirements.

  Methods  Based on STAR-CCM+ overlapping grid technology and the Dynamic Fluid Body Interaction (DFBI) and Volume of Fluid (VOF) wave models, the dynamic simulation of the floating process of an unpowered vehicle is carried out using the CFD numerical calculation method. The effects of the specific gravity of the unpowered vehicle itself, positions of the mass and buoyancy center, rudder angle, initial launch velocity on its inclined climbing and floating parameters, and water-exit attitude are studied.

  Results  The results show that when the net buoyancy is 0.15 displaced weight of the vehicle, the pitch angle of the vehicle is stable at around 45 degrees; when the net buoyancy is 0.10 displaced weight of the vehicle, the vehicle will experience a swing process in the course of inclined climbing; it is not the case that the greater the net buoyancy, the faster the vertical velocity of the vehicle, but the smallest vertical velocity is when net buoyancy is 0.20 displaced weight of the vehicle.

  Conclusions  The results of this study can provide references for the overall layout and control design of unpowered vehicles, as well as the feasibility analysis of the application of unpowered vehicles in other fields.