车体-喷水推进器耦合作用对水陆两栖车水动力性能影响研究

Coupling Effect of Vehicle Body and Waterjet Propulsion on Hydrodynamic Performance of Amphibious Vehicle

不同于传统水面船舶,水陆两栖车涉及陆上行走与水上航行两种工作模态,探索和理解喷水推进器与车体的相互作用必不可少。该研究基于计算流体力学(CFD)方法,建立了两栖车-喷水推进器耦合数值模拟方法,计算了约束条件下的水陆两栖车航行特性,开展了进水流道及叶轮-导叶对车体稳性及阻力的影响研究。通过数值计算结果和模型拖曳试验的比较分析,验证了CFD方法在两栖车水动力性能预报中的有效性。计算结果表明:进水流道和叶轮-导叶对两栖车水动力性能的影响显著,与裸车体相比,在航速Fr=0.953,纵倾角度θ=10°时阻力值差异分别为2.03%和4.77%;两栖车钝体外型结构会影响流道入流均匀性,周围流场和管内流动差异随航速和纵倾的增加而增大,叶轮运转会促使流动分离区漩涡发生明显偏移,进而影响出口流场。

Different from traditional surface ships,amphibious vehicles involve two working modes:land walking and water navigation,so that the interaction between vehicle body and waterjet propulsion is essential to explore and understand.Based on the computational fluid dynamics(CFD)method,a coupling numerical simulation method of amphibious vehicle and waterjet propulsion is established to simulate the navigation characteristics of amphibious vehicles under constraint conditions.The influence of inlet duct and impeller-guide vanes on the stability and resistance of the vehicle body is studied.By comparing the numerical results with the model towing test,the validity of CFD method in hydrodynamic performance prediction of amphibious vehicles is verified.The results show that inlet duct and impeller-guide vanes have significant impact on the hydrodynamic performance of amphibious vehicles.Due to the influence of the inlet duct and impeller,at speed Fr=0.953 and pitch angle θ=10°,the difference between the calculated results and those of the bare vehicle body is 2.03%and 4.77%,respectively.The uniformity of inlet flow is affected by the blunt body structure of amphibious vehicles,and the difference between the surrounding flow field and the inner flow inside increases with the increase of speed and trim.The vortex in the flow separation zone is obviously offset due to the impeller operation,which affects the outlet flow field.