Resistance reduction optimization of an amphibious transport vehicle

The resistance reduction optimal design of amphibious vehicles is essential to improve efficiency and reduce energy consumption. In this paper, the hydrodynamic characteristics of an amphibious transport vehicle are investigated by Computational Fluid Dynamics (CFD) method based on the Reynolds-averaged Navier-Stokes (RANS) solver. A set of towing tests are conducted to verify grid independence and computational accuracy. Four typical shape control parameters are selected as optimal design variables and the independent effects of each variable are analyzed. The sample set is obtained using Latin Hypercube Sampling (LHS), and corresponding three-dimensional models are generated based on the parameters of each sample point. CFD calculations are then used to obtain the resistance characteristics of the models. The Kriging method is utilized to establish an approximate model, and the credibility of the model is verified. The Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) is used to find a global optimal solution or set based on approximate models. Two optimized configurations, Opt1 and Opt2, are obtained, corresponding to single- and multi-objective optimization results, respectively. At the design speed of the amphibious transport vehicle, Opt1 has the highest resistance reduction rate of 12.7907% under the full load condition, while Opt2 has resistance reduction rates of 11.0863% and 8.5293% with and without load, respectively.