Objective  sThe design of stern flap usually focuses on resistance reduction at high speed. For surface warship stern flap design which is aimed at optimizing the cruise speed and design speed, the cruise speed comes in a large range, so the parameter selection of stern flap needs to be emphasized.

  Methods  The design method combining viscous wave making flow field numerical simulation and model test verification, which take into account the navigation attitude, is used for optimization of stern flap with multiple condition parameters. Through comparative analysis on multi-option numerical simulation and resistance and self-navigation model test, the the influence of length and cathedral angle of stern flap on the resistance reduction and energy saving in the cruise speed and design speed of displacement surface warship is learned and a preliminary analytical verification of the effectiveness of CFD numerical simulation results is done.

  Results  The results show that, by optimizing the stern flap parameters, energy consumption is reduced by 3% in cruise speed and 5% in design speed, thus the goal of energy saving in both cruise speed and maximum speed is achieved.

  Conclusions  The research can provide theoretical support for the subsequent parametric optimization design of stern flap of displacement surface warship.