层化海洋环境下潜艇水下航行阻力及兴波数值研究

Numerical Research on Underwater Navigation Resistance and Travel Waves of Submarine in Stratified Ocean Environment

基于计算流体力学(CFD)方法对采用SUBOFF标模的潜艇在层化海洋环境中航行问题进行数值模拟,考查航行速度、相对内界面位置、潜艇相对潜深、上下层流体密度对航行阻力和水面兴波的影响。研究发现,潜艇航行阻力系数随内界面弗劳德数Fr_(n)的增大先增大而后减小;在Fr_(n)=0.9左右取得最大值,随后减小并在Fr_(n)>2之后基本保持不变。在低速状态下,潜艇航行阻力系数在内界面以下时较大,在内界面处最小。在高速状态下,阻力系数曲线基本不随Fr_(n)变化而改变,潜艇在内界面处阻力系数最大,在内界面以上时最小。自由水面兴波模态随Fr_(n)增加逐渐由亚临界模态变为超临界状态,由存在横波和散波变为只存在散波。水面兴波波幅随Fr_(n)增大而增大,波长和波形夹角随着Fr_(n)增大而减小。数值结果中,自由水面兴波情况不随相对潜深的改变而改变。

Based on the computational fluid dynamics(CFD)method,the navigation problem of submarine using SUBOFF standard model in layered marine environment is numerically simulated,and the effects of navigation speed,relative position of inner interface,relative submergence depth,fluid density of upper and lower layers on navigation resistance and surface wave-making are investigated.It is found that the navigation resistance coefficient of submarine first increases and then decreases with the increase of the number of internal Fr_(n),reaches its maximum value around Fr_(n)=0.9,then decreases and remains basically unchanged after Fr_(n)>2.At low speed,the navigation resistance coefficient of submarine is larger below the inner interface and smallest at the inner interface.At high speed,the resistance coefficient curve basically does not change with the change of internal Fr_(n) number,and the resistance coefficient at the inner interface of submarine is the largest,while the resistance coefficient above the inner interface is the smallest.With the increase of Fr_(n) number,the wave-making mode of free water gradually changes from subcritical mode to supercritical mode,and from shear and scattered wave to only scattered wave.The amplitude of surface wave increases with the increase of Fr_(n) number,and the included angle of wavelength and waveform decreases with the increase of Fr_(n) number.In the numerical results,the wave-making in the free water surface does not change with the change of relative submergence depth.