密度分层流中浅航艇兴波尾迹分析

Analysis on the wake of a shallow navigation submarine in the density-stratified fluid

为研究由密度差引起的分层流对浅航艇兴波尾迹特性的影响。基于RANS方程,采用Realizable k-ε湍流模型,结合用户自定义函数(UDF)方法建立了用于密度分层流中潜艇兴波尾迹特性分析的多相流CFD模型。采用此模型针对SUBOFF全附体潜艇在密度分层流中不同位置处以不同航速(低速、中速、高速)浅层航行时的水动力性能开展了模拟,分析了航速、航行位置、密度分层等参数对潜艇在各交界面处兴波尾迹以及水质点速度分布特性的影响。研究结果表明:潜艇航速越高,并且距交界面越近,在各交界面上的兴波将越剧烈,尾迹越明显,尤其在中速阶段,潜艇将激起较大的兴波;自由液面与内波面兴波波形区别较大,主要表现为自由液面处兴波前端为波峰而内波面处兴波前端为波谷;内交界面处兴波对各参数的敏感度较自由液面的要低。本数值模型具有较高精度,可为密度分层流中航行潜艇兴波尾迹特征分析提供一种有效的手段;模型给出了潜航艇在不同工况下的航行特征,可为密度分层流中潜艇规避策略的选取提供参考依据。

To study the wave-making characteristics of a shallow navigation submarine in the stratified fluid caused by density difference,a multiphase-flow CFD model for evaluating the wave-making characteristics is established by using the RANS equation,Realizable k-εturbulence model and UDF method.Thereafter,the process of a full-appendage submarine navigating at different positions with low,medium,and high forward speeds in the shallow layer of density-stratified fluid is simulated,and the effects of the forward speed,the distance from interfaces and density-stratified fluid on the wave-making and velocity characteristics of the submarine in the interfaces are investigated.The result shows that the higher the forward speed and the closer to the interface are,the more intense the submarine wave-making in the interfaces will be.Especially in the mid-speed stage,there will be a large wave excited by submarine,and a big difference of wakes between the free surface and internal wave surface is obviously seen,of which the main performance is that the front of wave on free surface is a peak and the front of wave on internal surface is a trough.The response of the wave-making on the internal interface to the changes of various navigation parameters is insensitive than that on the water-free surface.The present numerical model has high accuracy,which can provide an effective method for analyzing the wave-making characteristics of submarine navigating in density stratified fluid.