Abstract: In order to study the ricochet phenomenon of trans-media vehicle entering into water at small angle, a numerical model is built based on CFX, and the accuracy and applicability of the model are verified. The ricochet progress of the vehicle with different vertex angles, different densities and variable truncated annular grooves while entering into water at small angle are simulated. The whole ricochet progress and the change rules of angular acceleration, angular velocity and displacement during the progress are analyzed. The research results show that small vertex and density of vehicle would lead to the upward curving of ballistic trajectory, thus the ricochet phenomenon is more likely to occur, and the angular velocity mutation is due to the strike of the tail of vehicle on the water surface in the inundation stage; the truncated annular groove ogive has certain inhibitory effect on the ricochet of vehicle, and the position of the annular groove is very influential to the process of water entry, which can be chosen according to the task demands.

Key words: ordnance science and technology, trans-media, water-entry movement, ricochet process, numerical simulation